Crazy strong Gorge East winds and El Norte winds for Baja…

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High pressure blankets mid USA creating strong pressure gradients.zz48cb69c1

by Mike Godsey, mike@iwindsurf.com

Tomorrow, Thursday Dec. 8, 2016 will see very strong east winds in the western Gorge to Portland while Baja’s East Cape sees significant El Norte winds. Surprisingly these winds, separated by thousands of miles of land, have the same cause.

But first let’s look at the NWS discussion for the Gorge tomorrow. While the models bicker a bit about the max strength of the Gorge winds it looks like we will see gusts in the 60-80 mph range at Rooster Rock. But what about that mention of 110 mph gusts? We will come back to that also.gorgeewinterwindsbaja

The cause of both the Gorge E. winds and the North winds in Baja is a enormous high pressure zone located in the middle of the USA. In the 2nd. image that high pressure zone is in red. Notice how the high pressure area is just east of the Gorge and north of Baja. Now notice the tightly wound low pressure storm system west of the Pacific Northwest. So the Gorge has strong low pressure to west and strong high pressure to the east. This means there is an extreme pressure gradient over the length of the Gorge. But the Cascades make a partial barrier to the winds created by this huge pressure gradient. So the main route for the east winds will be in the Stevenson to Troutdale corridor. So the venturi effect will be strongest there.

This pressure gradient is so massive that if all of the winds was near surface wind we would be seeing gusts to 110 mph range. But tomorrow there is strong wind from the surface to over 5000 feet. This means a good portion of the wind will be able to slip over low places in the Cascades rather than being focused just in the Gorge.

Now looking at Baja notice that the huge high pressure zone is partially over the Great Basin  and 4 corners zone. High pressure in that zone creates a pressure gradient to the frequent low pressure zones south of Baja. This pressure gradient should create solid El Norte winds tomorrow.

Now note the location of the North Pacific High. This is location is far to the south of the North Pacific High’s summer time residence off our west coast. In recent years the North Pacific High has been even further south so it is often sending NW to WNW winds over Baja pushing the El Norte N-NNE winds  away from the shore especially at El Sargento  and sometimes La Ventana. But tomorrow it looks like the North Pacific High is positioned so it will actually jazz up the El Norte winds.

 

 

 

Posted in Cape Cod, Los Angeles, San Diego, San Francisco

Another Short Wave Wind Killer for Charleston, SC.

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by WeatherFlow meteorologist Shea Gibson

We have discussed short wave troughs (known as “short waves”) before in previous blogs, but here is a quick recap:
According to NOAA’s definition, this is, “A disturbance in the mid or upper part of the atmosphere which induces upward motion ahead of it. If other conditions are favorable, the upward motion can contribute to thunderstorm development ahead of a shortwave trough.”
Also see my focused blogs on past short wave events:

June 2, 2015: http://blog.weatherflow.com/what-is-a-short-wave-and-how-can-it-affect-winds/ 
April 19, 2016: http://blog.weatherflow.com/never-forget-the-short-wave/

On November 1, 2016, we saw High pressure to the north set up a fairly solid and moderate NE Wedge down the SE Coast. Specifically, Charleston, SC is know for accelerations of speeds due to Sea Breeze coupling as cool air dives down over warmer waters and intensifies along the barrier island beaches. This is known as “backdoor Sea Breezing” when a “backdoor” cold front has moved down the coast and High pressure wedges in down behind it. In this case, a weak cold front moved through and slowly fizzled out over SC/GA.

Here in the WPC NCEP surface map from 7:00am, a tail end of troughing still remained offshore.
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At 7:47AM, the NE/ENE winds picked up to 16kts g20 (gusting to 20kts) due to the sun coming up, the gradient tightening and speeds elevating according to the onshore turn/acceleration process of initial Sea Breezing.
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Quick note: Air Temps were already in the upper 60’s, so the radiational heating process in the atmosphere got things going earlier once the sun came up.
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By midday to 12:55pm, the backdoor Sea Breeze process had winds up to 18kts g22, which we consider a moderate flow.
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A little after 1pm, the drain got pulled on the winds and speeds plummeted. By 1:38pm-1:42pm speeds north of the Charleston Harbor had dropped to 10/11kts. Folly Beach kept its speeds to 18kts g21.
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My first reaction was to check radar, but no precip showed up. Took a look at the sky and saw cloud layering with overcast-type skies. That was my first clue that short waving was occurring somewhere nearby. I brought up the SPC Mesoanalysis, which I have set to update every 1 minute – and caught a small atmospheric disturbance to the south:
The positive tilt (upwards bow) in the High pressure 1022 isobar (equal line of pressure) was representative of a short wave trough developing. Counter-clockwise rotation in the surface wind barbs are a classic signature of a short wave beginning to allow for weak surface low pressure development. You can see the showers showing up on the radar imaging. This was likely initiated by a bit of rotation intensifying over the warm waters of the Gulf Stream. 
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So looking at our Datascope viewer, I was able to capture the short wave developing into a weak low (mesolow) and heading into northern Georgia. The outflow aloft showed that the gradient held up just south of the Charleston Harbor, but clouding aloft cut off the flow to the north. It was actually sunnier to the south within an open pocket in the clouding, which kept the Sea Breeze alive to Folly Beach a bit longer.

Here is a different perspective from WSV3:

Eventually, areas to the south including Folly Beach saw the drop in winds. Just took a little longer. Here is the graph of Folly Beach that day – you can see the downward trend around 1:45pm:
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All-in-all, this is yet another way we can detect short waves by first analyzing our coastal mesonet and then using the sky as another reference point before even checking regional radar or the regional mesoanalysis.  Many times, just knowing the NE/ENE wind behavior and knowing that a sudden drop of onshore flow usually means either a) a short wave/area of low pressure weakens the gradient from nearby (common) or b) the overall gradient weakens just that fast (not very common).

Until next time – stay safe out there.

Cheers!
Shea Gibson
WeatherFlow Forecasting Team
East Coast/ SE Region
Outreach/New Station Projects
Twitter: @WeatherFlowCHAS

 

Sources: NOAA SPC, NOAA WPC NCEP archives, WSV3, and our own WeatherFlow Datascope Professional Viewer 

Posted in Coastal South Carolina

Beware the Witch of November!

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by WeatherFlow meteorologist Shea Gibson

Get ready Great Lakes for a possible “November Witch” to broom into the area by Thursday/Friday with a cauldron of warm air, cold air and violent gales! The name comes from intensifying Low pressures with a clashing of warm air, rain and storms ahead drawn up from the Gulf of Mexico…and cold Canadian air with heavy snow wrapping down around it. At times in the past, we have seen hurricane category force 1 and 2 winds generated over the Great Lakes as the two air masses collide. This is typically a more frequent event to see this time of the year; however, the effects of a La Nina pattern have kept warmer air up across the upper midwest until this week as we see the pattern begin to act more like the fall season.

The old saying goes: “Beware the Witch of November!”

The Witch of November phrase was used in the famous song “The Wreck of the Edmund Fitzgerald” (happened in 1975) by Canadian singer-songwriter Gordon Lightfoot, which was a tribute to one of the most well-known Great Lakes shipwrecks known in that area.

Artistic rendition of an angry and cruel Lake Michigan.

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And the “pointy hat” of a “cruel witch” from Photographer Dave Sandford.

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S.S. Edmund Fitzgerald before it went down in Lake Superior on November 10, 1975. All 29 of its crew perished. Between 1878 and 1987, 6,000 ships have been lost on the Great Lakes…with upwards of 25,000 individuals losing their lives over the last 300 years.

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Sadly, the National Weather Service Marquette, WI did issue fair warning ahead of their departure, but they went anyways.

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GFS model surface run showing a possible 987mb Low (very strong winds are typically generated at this pressure)

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GFS 500mb chart showing the strong mid level vorticity just west of the Great Lakes by Friday afternoon.
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ECMWF (EURO model showing agreement with lower pressure at 982mb’s.
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San Francisco State University 300mb (~30,000ft)  jet stream analysis showing an intense dip in the jet stream with strong Southerly flow aloft pushing over 100kts – with higher areas of streaking to the SW and the NW.
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As we head into Saturday, we see winds pick up across the Great Lakes:

Here is the GFS wind forecast for (Lake) Superior West Buoy topping 30mph – the CMC Canadian model (yellow line) reaches into the 40’s.
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And here is the forecast not too far away at Stannard Rock in Lake Superior as well:
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Even though this is still 5-6 days out with much that could change, it does serve as plenty of heads up to mariners up that way to keep an eye on developing conditions this week.

UPDATE 11/18/16: Looks like this storm verified with wind in excess of 50mph over Lake Superior and other locales where the wrap-around winds are really cranking up. Here is a video of the system and the winds + gusts.  Snow and blizzard conditions are on the N/NW/W/SW side of the system where cold air is wrapping into it… with white-out conditions for many locales.

Stay safe everyone!
Shea Gibson
WeatherFlow Meteorologist/Wind Forecaster
SE Region/East Coast/Tropics

Outreach & New Station ProjectsHow to find me:
Twitter: @WeatherFlowCHAS
Facebook:
Wind Alert – https://www.facebook.com/windalert/ 
WeatherFlowCHAS – https://www.facebook.com/WeatherFlowCHAS/
Chucktown Wind Report – https://www.facebook.com/groups/ChucktownWindReport/

Sources for this blog: Our own Datascope viewer, Tropical Tidbits (Levi Cowan), WeatherBell Analytics, NWS Marquette, WI , SFSU.edu, Photographer Dave Sandford

Posted in Ontario- Simcoe, Ontario: Lake Erie, Ontario: Lake Ontario, Weather Blog

Winter arrives and the North Pacific High departs while…

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Storms dominate northern pacific

by Mike Godsey, mike AT iwindsurf.com

Remember this summer when the North Pacific High dominated the waters between the west coast and Hawaii? Back then wind most days was a given. So where did the Southern California, Bay Area and Gorge winds go?

Part of  the answer is the decreased hours of sunshine to heat inland valleys. And then there is the lower winter angle of the sun which promotes less heating. Both of these factors mean the
pressure gradients from the coast to the Southern California deserts, Columbia Basin, Central Valley and the Great Basin are much weaker in the late fall and winter.

But a large part of the answer is the location and size of the North Pacific High. During the summer the upper troughs up at ≈ 18,000 ft. that pass over the west coast take a more northerly path. As they graze the Gorge the just act to indirectly jazz up the surface winds. While in the S. F. Bay Area and Southern California they deepen the marine layer and in so doing impact the strength and location of the wind.

But in winter the upper troughs take a more southerly track bringing storms and rain to the west coast as they guide surface storms towards us. And this more southerly track plays a role in moving the North Pacific High to a winter home often well south of the west coast.

In this animation I have removed the clouds so we can more clearly see the wind patterns as well and rainy storms and high and low pressure systems.winternph

First notice the relative small North Pacific High in the lower right corner of this image of pacific and west coast. Notice that its clockwise winds are creating weak NW winds along the coast of Baja. Back in the summer the NPH was much larger and located west of Northern California.

Now notice the huge pacific storm and its counter-clockwise spinning winds that is slowly plodding towards the Pacific Northwest. The bands of rain in this storm are in green. Also notice the cold front associated with this storm.

Next notice the developing high pressure in the 4 corners area of the USA. This high pressure moved in in the wake of the recent storm and should make for a mild El Norte wind event in Baja’s Sea of Cortez tomorrow and/or Tuesday.

Come spring the average path of the upper trough at ≈ 18,000 ft. will slowly move north and you will see the storm track move northward. And as spring progresses the average position of the North Pacific High will be in California waters and the stage will be set for NW clearing winds.

Posted in Columbia River Gorge, Los Angeles, San Diego, San Francisco

Big East winds in western Gorge created by….

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Major wintery storm off the coast.stormswgorgeeast

by Mike Godsey, mike AT iwindsurf.com

There are a number of causes of east winds in the Gorge.

The most common cause in early fall is the departure of the North Pacific High from our waters and high pressure developing in the Great Basin  and Columbia Basin. This means a pressure gradient from east to west. This is never a huge pressure gradient so the winds in most of the Gorge are very weak. But all that easterly wind has only one pathway to the  lower pressure over the ocean. And that is the narrow gap in the Cascades in the Stevenson to Rooster Rock area. So while the Hatch and Swell may see only a few knots of east wind Stevenson and Rooster may be ripping in the 30’s.

But in late fall there can be another cause of east winds in the Stevenson to Rooster Rock area and this cause is always associated with strong southerly winds on the coast.

As you can see in these images todays strong dawn winds at Stevenson to Rooster Rock area were triggered by a deep lowewindsgorgeswindscoast pressure storm system off the coast of the Pacific Northwest. So all the air in the Columbia Basin begins to move towards that low pressure. And once again the Stevenson to Rooster Rock area acts as an venturi so the winds accelerates in that area. Then once past this narrow gap in the Cascades the winds diverge and weaken. Meanwhile the coast is being battered by strong southerly storm winds.

Also notice how much weaker the wind is just a few miles away from the coast and in the lee of points along the coast. Once again topography plays a role. These storm winds are unstable air and when unstable air hits hills, points and ridges it rises and is slow to return to the surface making for weaker surface wind.

Posted in Columbia River Gorge

2016 Fall Marine Layering Starts

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By WeatherFlow meteorologist Shea Gibson

It’s that time of the year for “marine layering” again as water temps have cooled to the low 70’s.  I’ve been recording when marine layering starts for the last 3 years in order to further document the initiating time periods. In the 2013, it started on Friday, November 1st. In 2014, it started much earlier on Friday, October 3.  In both 2013-2014, we saw a 3-5 degree drops in two separate occasions with cold air intrusion and more NE/ENE events (“NE Wedge”).  In 2015, it was a less substantial all-at-once drop and more of a progressive subtle feature that occurred during the October Rain Storm of 2015. This year we again saw a more progressive marine layering process as water temps slowly fell, with a double NE Wedge setup + Hurricane Matthew making landfall just north of Charleston along Copahee Sound/McClellanville, SC.   The storm certainly plunged the water temps down several more knots as it stirred the surface, resulting in cool water upwelling followed by another NE Wedge and a cool air mass from the north.  For this marine layer date, I place the initiation on Tuesday, November 18th.

Review:
The thing to remember here is that warm air masses tend to cause wind speeds to “decouple” over the cooler, more stable waters. This means that a layer of cooler air hangs over the cooler surface unless warm air is able to penetrate and mix into it for instability (instability = wind). Higher humidity levels are said to be a large part of the reason for decoupling; however, even with dry air over the coastal region, these layers create their own higher humidity levels at the surface. They are in many cases, their own body of dense cool air surface pooling.

See the previous blogs for past history:
2013: http://blog.weatherflow.com/1st-marine-layering-event-affects-se-region/
2014: http://blog.weatherflow.com/marine-layering-effects-start-in-the-se-region/
2015: http://blog.weatherflow.com/2015-fall-marine-layering-starts/
DETAILED ANALYSIS: http://blog.weatherflow.com/drawing-a-line-in-the-water/

We can see the trend from October 3 to near present yesterday 10/23/2016 in the NASA Sport SST animation, where coastal shelf waters along the immediate coast fell to around 73/74°…and have now fallen to ~72.3° as of today 10/24/16. You can also see the swirl, or surface eddy, that Matthew caused between October 8-10th in the warmer Gulf Stream well offshore.

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Waters were ~81° on October 3, then a NE Wedge setup dropped waters a few degrees. Then Hurricane Matthew wobbled up the coastal SE Region on October 7-9 to further the cooling. Here is the SST from October 12 after Matthew was gone and the next NE Wedge pushed speeds further down to 72.7°.

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We also saw an upwards surge in temps after that cooling period, but only made it to a bit over ~75°. Now we are at 72.3° as of October 24 due to a seasonal shot of Canadian air that recently made its way down into the SE. Here is an edited NOAA/NOA/CO-OPS Sea Surface temp chart going back to Oct 3. Notice the progressive trend, which is considered a normal timeline for cooling.

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Ok so how did this affect the winds and how does this relate to marine layering?

I usually try to use a good bench mark, such as a strong cold front with a warm air mass ahead of it, to test for marine layering since we need warmer air over cooler waters. However, we can also look at our Southerly Sea Breezes with High pressure in the Atlantic creating the warm air mass as well.

Here are the wind obs from Tuesday, October 18 (at 2:59PM) and Wednesday, October 19th (2:57PM) showing winds just inside the Charleston Harbor next to Fort Sumter a few knots higher than at the beaches on a straight South direction.

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The air temps that day went all the way up to 87/88° around 15 miles inland at the Charleston International Airport. However, air temps were only 76-77° over the Chas Harbor and along the beaches with the cooler onshore flow.

The climate pattern for Tuesday and Wednesday consisted of a weak Bermuda ridge (weak Atlantic High pressure) allowing for modest Southerly Sea Breezes and hot air. The difference between the coastal break speeds and the beach speeds is a symptom of subtle marine layering where the beaches show less speed due to cooler SST’s (72.5-73°). Morris Island is just to the south of Fort Sumter, which provides the upwind land heat for higher speeds (wind mix down to the surface).
The line is very small between where it starts and where it ends, and you can see on some days during S/SSW/SW winds where it will be 25kts just inside the harbor and 10/11kts along the beaches  – read my detailed blog about it here for more information: http://blog.weatherflow.com/drawing-a-line-in-the-water/

The layer may be too shallow for the naked eye on some days, but it can be often seen as a thin “haze” when the first signs show.  The cooler the water temps and the hotter the air temps, the more visible this becomes- eventually becoming a very thick fog bank over the barrier islands.

Here is a pic from 2013 I took showing the thin haze looking from Sullivan’s Island towards Isle of Palms across Breach Inlet.
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Here is a couple of pics from Rusty Williamson from Tuesday morning, October 18 from 3rd Street Isle of Palms facing SSE (tip of Sullivan’s Island far right). You can see the haze across the waters. Tuesday morning presented a shallow steam layer as low temps were near 64° as the sunrise added heat. This layer stuck through the day once air temps surpassed SST’s, but became less visible into the afternoon. I did notice a shallow haze layer remaining across the harbor that day during peak heating.

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Last week on Friday, October 21st, we had a cold front drop into the SE Region with a warm air mass ahead of it, but the front did not develop over our area and it stayed fairly dry. The winds did, however, line up from the SSW/SW ahead of the front with air temps reaching mid to upper 80’s. The below radar loop was from the morning showing the cold front approach.

Now the SST’s had climbed back up to near ~75° – 76° by this time, so the marine layering was not an issue.
[The 76 degree mark has always been my theory on where the phenomena ends and where it begins. And usually in the spring, the cannonball jellyfish let us know it will be soon when SST’s will be rising above that mark. More on this here: http://blog.weatherflow.com/cannonballs-fire-the-first-warming-shot/ ]

Here are the wind obs from this past Friday- notice the coupling at the Isle of Palms beach showing low to mid teens (just like in the harbor) between 12PM-2:00PM. Then we see the post-frontal flow crank up in the harbor.

Fort Sumter just inside the Charleston Harbor:
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Isle of Palms Pier sensor (beach side):
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So now we are back into the low 70’s with overnight lows expected to get us down near 70° this week, if not upper 60’s. We do have 2 weak backdoor cold fronts approaching today and later in the week on Thursday/Friday, so we’ll get to see further evidence. If significant, I will update here in this blog.

Until then or this spring when the marine layering ends for annual documentation…

Cheers!

Shea Gibson
WeatherFlow Meteorologist/Wind Forecaster
SE Region/East Coast/Tropics
Outreach & New Station Projects

How to find me:
Twitter: @WeatherFlowCHAS
Facebook:
Wind Alert – https://www.facebook.com/windalert/ 
WeatherFlowCHAS – https://www.facebook.com/WeatherFlowCHAS/
Chucktown Wind Report – https://www.facebook.com/groups/ChucktownWindReport/

Sources for this blog: NASA SPoRT, WSV3 radar software, NOAA Tides and Currents, Rusty Williamson on Twitter

 

 

 

 

 

Posted in Coastal Georgia, Coastal South Carolina, SouthEastern North Carolina

Washington/ Oregon Seeing a Powerful 1-2 Punch this Weekend.

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By Weatherflow meteorologist Shea Gibson

Washington and Oregon have been seeing some very strong winds and dangerous conditions since yesterday and into today. The strong wind belt aloft known as the “North Pacific Jet” (NPJ for short) is taking a dive down over the region with a surge of energy from ex-Typhoon Songda, one of the northernmost super typhoons on record. This is bringing some rather nasty weather their way now – with stronger activity to come. It is their version of the powerful Nor’easters we see on the East Coast at times, but these have a different dynamic setup over the northeast Pacific.

Here is Super Typhoon Songda at its strongest profile. It peaked out October 11, with JTWC reporting (1 minute sustained) winds of 150 mph and pressure at 925 mb. Songda ultimately raced to the NE and got pulled up along the NPJ:
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Current jet stream at 250mb (~34,000ft) that Songda was pulled into. The downstream disbursement of energy (or correlation) of one phenomena to another distant location is known as “teleconnection”.  The storm we are seeing come together now is a result of that relationship.

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Here is a sped up version of Songda’s track:

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This screen grab was from Jim Cantore of The Weather Channel on the local storm reports from yesterday/last night – notice the high winds reported! Some of these were at higher elevations.
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One powerful upper Low is moving over now (as of 1730 UTC)…with another stronger upper Low slated to come in behind it tomorrow.

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You can see the jet stream speeding up aloft with an atmospheric river diving down it – this will instigate faster progression of the next storm.

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Jet Stream speeds are expected to reach 150kts by Sunday morning. Winds will be very strong in the higher elevations in the mountains Sat night through Sunday.
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There was a LSR report that came out today that showed a confirmed hail and at least one (currently listed) EF-0 tornado in Manzanita, OR this morning – a very rare sight!
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And a chilling video to go with it!

Apparently there have been more! The US National Weather Service Portland, Oregon, as of 7:30PM tonight, made this statement via their Twitter acct:
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NWS Seattle issued this today as well:
cuwm7emvyaejtw1The 5-day WPC rainfall totals are pretty staggering as you can see – these numbers are in inches.
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Wind speeds will be reaching possibly in excess of hurricane force speeds in gusts for many spots (especially at the higher elevations).  Right now, winds are gusting pretty high around the area. Some locales are seeing winds come down…for now.
Destruction Island:
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Steamboat Flats (just north of Seattle, WA) -25FT AGL (ZERO ft ASL)
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This came from Dr. Ryan Maue of WxBell Analytics today explaining the significance of the event. The lower mean sea level pressure (MSLP) is a sign of intense strength for the storm.
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Pressures are already below 1000mb for most spots now (5PM PDT).
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Batton down the hatches over there Washington and Oregon! We hope everyone is ok after this one passes. We’ll keep up with the unfolding event over the next 24-48hrs.

Stay safe!

Shea Gibson
SE  Region/East Coast/Tropics
Outreach & New Weather Station Projects
Twitter: @WeatherFlowCHAS
Facebook: Shea Gibson – WeatherFlow, Wind Alert

Sources: Digital-Typhoon.org , Earth.nullschool.net, Twitter, our own Datascope products with WeatherFlow, Inc. , Dr. Ryan Maue of WxBell Analytics , Weather Prediction Center , NOAA GOES West, NWS Portland on Twitter, Jim Cantore on Twitter from The Weather Channel, AcaFeLLas, NWSChat LSR reports , SFSU Meteorology , RAMMB CIRA Colostate

Posted in Columbia River Gorge, San Francisco

10/5/16 3:00PM Hurricane Matthew Update

By WeatherFlow meteorologist Shea Gibson

 

Stay safe!

Shea Gibson
SE  Region/East Coast/Tropics
Outreach & New Weather Station Projects
Twitter: @WeatherFlowCHAS
Facebook: Shea Gibson – WeatherFlow, Chucktown Wind Report

Posted in Chesapeake Bay, Coastal Georgia, Coastal South Carolina, Delmarva, Outer Banks of North Carolina, SouthEastern North Carolina, Tidewater Virginia

Hurricane Matthew update 10-3-16 9:40PM

By WeatherFlow meteorologist Shea Gibson

 

Stay safe!

Shea Gibson
SE  Region/East Coast/Tropics
Outreach & New Weather Station Projects
Twitter: @WeatherFlowCHAS
Facebook: Shea Gibson – WeatherFlow, Chucktown Wind Report

Posted in Cape Cod, Chesapeake Bay, Coastal Georgia, Coastal South Carolina, Connecticut, Delmarva, Long Island/SE New York, Long Island/SE NY, Massachusetts North Coast, New Jersey, Outer Banks of North Carolina, Rhode Island, SouthEastern North Carolina, Tidewater Virginia, Weather Blog

Major Hurricane Matthew 8AM Update 10/3/16

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By WeatherFlow meteorologist Shea Gibson

10/3/16 8AM Update on Hurricane #Matthew: Still a Category 4 major hurricane with winds at 130mph, pressure 943mb’s, heading N at 6mph towards western #Haiti and eventually up through eastern #Cuba.

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Looks like #Jamaica may get spared the stronger core winds. Hurricane Warnings are up for all of these areas. Beyond Cuba, the northward track takes it up into the Bahamas Wed through Thursday while still maintaining major hurricane status – estimated Cat 3. The system could weaken to Cat 2 status once pushing into the northern Bahamas and beyond.

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At 5 days out, we are still uncertain of the degree of nudge towards the SE coast from Bermuda High pressure and northern High pressure, but for now model guidance is keeping it very close to northern SC and southeast/OBX NC.  We will need to watch peripheral patterns very closely to see just how much of a westerly nudge it may receive…or how fast a pull out to sea may happen.

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This is a timing issue with forward speed and overall system patterns once it enters the heart of the Gulf Stream off the FL coast, where sea surface temps are still very warm near ~86°. Cooler shelf waters are between 80-83° west of the Hatteras-Florida Slope and into the coast (see below graphic).

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Here is the NASA Sport SST with edits to show the features.

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The chances are slowly increasing that we may see some outwards effects from this storm along the SE coast. Expect in the very least strong rip currents and higher than normal swell heights. We could see strong winds by late week and into the weekend depending on the track of Matthew. Moderate NE winds may pick up by mid week due to increasing pressure gradient with High pressure to the north and troughing near the SE coast…and may continue to build from there with the outward wind field increasing. We’ll have a much better idea once it passes through Cuba and heads towards the Bahamas.

By the way…check out the 34ft waves Matthew kicked up at the Central Caribbean buoy while going over it.

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And the cool water upwelling due churning of the waters. Notice about a 7 degree drop in water temps.

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For now, stay tuned and keep a good eye on the latest 3hr updates from the NHC (8am, 11am, 2pm, 5pm, etc…):http://www.nhc.noaa.gov/

Stay safe!

Shea Gibson
SE  Region/East Coast/Tropics
Outreach & New Weather Station Projects
Twitter: @WeatherFlowCHAS
Facebook: Shea Gibson – WeatherFlow, Chucktown Wind Report

Sources: Tropical Tidbits , US National Hurricane Center , NASA Sport SST , National Data Buoy Center

Posted in Cape Cod, Chesapeake Bay, Coastal Georgia, Coastal South Carolina, Connecticut, Delmarva, Long Island/SE New York, Long Island/SE NY, Massachusetts North Coast, New Jersey, Outer Banks of North Carolina, Rhode Island, SouthEastern North Carolina, Tidewater Virginia