Wednesday, August 31, 2016

Lots of Weather to Talk About

As of 5 AM this morning there is a Hurricane Warning for the Big Island of Hawaii and a Hurricane Watch for portions of Florida.  Meanwhile Hurricane Gaston is a still a major Category 3 Hurricane in the open Atlantic and Tropical Depression 8 is pushing south and east of New England.  I'll get to all the tropical mischief in a moment but first lets touch on the Southern New England forecast.

General Overview
High pressure is set to move offshore today as a cold front approaches from the west.  This will being a return of the humidity this afternoon and will also increase rain chances tonight and Thursday.  The front will also help kick TD 8 out to sea and pull TD 9 (or likely Hermiine) Northeast into the Big Bend of Florida.  Here is the water vapor satellite loop from this morning
GOES East Water Vapor GIF 2 AM-4 AM (image NOAA)
Gaston is racing away on the far right while TD 8 is the thunderstorm complex off the NC Outer Banks and TD 9 is the thunderstorm mass in the Gulf.  The front is the clouds and moisture Missouri, Illinois and Michigan.  Here is the surface map
WPC 2 am surface analysis 
In terms of our weather there will be a mix of sun and clouds today with temps in the mid 80's.  Dew points will be in the mid 60's as well.   The rip current risk will be moderate today for all Southern New England beaches as a 3-5 ft swell from TD 8 and Gaston impacts the shore.
NWS Boston SNE Surf forecast 
Rain showers will move into Western New England later around 11 PM-midnight.  Some heavier showers could drop up to an 1" of rain in Western and Northern MA but most of us can reasonably expect a quarter of an inch of rain.  The AM commute is likely wet tomorrow.  Here is the simulated radar for 8 AM
06z NAM hires simulated radar 8 am (image College of Dupage WxCenter)
Rain pulls away by 2-3 PM leaving behind an air mass with max temps in the 70's and dew points in the 50's.  A perfect early fall preview for Friday and perhaps Saturday before we have watch what TD 9 does.

Tropical Update
First lets go to Hawaii.  Actually most people would want to avoid Hawaii as Hurricane Madeline heads toward the Big Island.
GOES Floater Rainbow infrared satellite Hurricane Madeline (image NOAA)
She is weakening but is expected to pass close to South Point if not right over.  Heavy rain, damaging winds and dangerous surf will accompany the storm.  A Hurricane Warning is in effect for the Big Island with Tropical Storm warnings posted further west.
Central Pacific Hurricane Center Track/Advisory for Hurricane Madeline
Closer to home TD 9 is ready to become a named storm and head towards Florida.  Given the available warmth in the Gulf and a more favorable upper level wind pattern this storm can intensify quickly.  For that reason the NHC has issued a Hurricane Watch/Tropical Storm Warning.
TD 9 NHC 5 AM track/forecast/warnings 
East of the center will see a dangerous storm surge while west of the center will see heavy flooding rains.  The storm surge potential is heightened in this part of Florida thanks to the concave curvature of the coast.  Now I'm sure attention is being paid to the 5 day part of the forecast and I see it and will evaluate this.  For now the potential for a crappy Sunday/Monday at the Cape is real.

-Zack Green

Sunday, August 28, 2016

The Weekly Weather Take 8/28/2016

Five years ago this morning power went out for many in Southern New England as Tropical Storm Irene moved up the east coast and into New England.  Irene brought devastating floods to Vermont and upstate New York as well as lots of wind damage to Southern New England.  The power would not be restored for 4-5 days for many.  Although Irene was a tropical storm its low central pressure and large wind field created widespread problems.  For me it remains one of the most memorable storms I have ever covered for this blog.

August 20, 2011- Irene forms
August 21, 2011- Irene moves by Puerto Rico and I make my first hurricane map
August 22, 2011- Irene moves by the Dominican Republic without weakening much
August 24, 2011- Irene moves through the Bahama's and a models show flooding rain potential
August 26, 2011- Irene approaches the Carolina coast 
August 27, 2011- Irene begins to move up the coast and Uxbridge floods
August 30, 2011- Irene wrap up 

Irene was my first my first major storm.  I certainly did more "wishcasting" than "forecasting" in terms of final track and wind speed.  I looked for reasons as to why and how the storm could hit New England and I missed out on the fact that Irene would be weaker and further west.  Here is some tree damage on Jon Circle in Whitinsville
Tree/power line damage August 28, 2011 (image Zack Green)
Here is flooding in Vermont from the storm
Flood waters from Tropical Storm Irene on the Ottauquechee River in Quechee, Vermont (image Wikipedia)
More Vermont
CNN Vermont flooding aftermath 
Storm surge damage in East Haven, CT
East Haven, CT storm surge damage (via UConn)
NWS Boston Irene graphic 
Irene shows that a tropical storm can be extremely disruptive to our lives.

Current Tropical Outlook
If you read my last blog you know the tropics are heating up.  There was much speculation about a tropical wave potentially hitting Florida or the Gulf Coast.  Even I said it reminded me of a certain storm from 11 years ago for South Florida.  That was wrong.  I used the name Katrina not for the New Orleans/Mississippi part of the storm but for the South Florida landfall in 2005 in which Tropical Storm Katrina strengthened right before landfall near Miami catching people off guard.  That's the only point I was trying to make but I realize you can't use the K word when forecasting.  It makes people uneasy.

Well the storm never formed which was always a possibility.  But we can't bury it yet- all signs point to something developing in 48-72 hours when the disturbance moves into the Eastern Gulf of Mexico.
NHC Atlantic Tropical Cyclone and Disturbances
But it now appears a new tropical depression off the Carolina coast will get the truly horrid name of Hermine while the Gulf system would be named Ian.  Gaston is a strong category 2 Hurricane making its way out to sea.  Tropical Depression Eight is forecast to move near NC before turning out.  Hopefully we can get some rain from it in Southern New England but it doesn't look likely.
NHC TD Eight track/forecast
Precipitation Outlook
Not much expected this week.
WPC 7 day precipitation forecast 
Not good.  Severe to extreme drought is in effect for over 70% of the commonwealth.
US drought monitor Massachusetts 8/23/2016
Weather links from the last week or so

1)  US Tornadoes takes a look at the "surprise" tornado outbreak from Wednesday.
2)  David Epstein of Boston.com takes a look at the overnight EF-1 tornado in Concord, MA.
3)  USA Today wonders why people didn't pay more attention to the Louisiana floods.
4)  Dr. Marshall Shepherd leads a round table on the tropical wave about to enter the GOM.
5)  Accuweather discusses Typhoon Lionrock as it approaches Japan (best name in the tropical game).
6) The Weather Channel discusses Tropical Storm Madeline and its potential to impact Hawaii.
7) After the earthquake in Italy experts warn about keeping the mafia away from the rebuild.
8) On this years anniversary of Katrina others need help from New Orleans.

I'll talk to you guys during the week!

-Zack Green

Wednesday, August 24, 2016

End of the Work Week Forecast

Its Wednesday and one of the last weekends of summer is rapidly approaching.  Here is the latest for the next several days.  After the general forecast I will discuss the Atlantic tropics.  

General Overview
High pressure remained in control today for more warm and beautiful weather.  Tomorrow the high is offshore and winds will increase out of the southwest ahead of a cold front.
WPC Surface forecast Thursday 2 PM 
Monday dew points were around 50.  Tuesday they crept up to 55 and today they are around 60. Tomorrow we inch a few more degrees higher into the mid 60's,
18z NAM hires 2 m dew points Thursday 5 PM (image Tropical Tidbits)
The good news is we stay dry during the daylight and evening hours Thursday.  Max temps are 85-90 across Southern New England.
NWS Max temps Thursday (Image Weatherbell)
Heading to the beach?  Surf will be a bit higher tomorrow thanks to an increasing southwest wind.  Moderate rip currents are likely for the beaches north of Boston.
NWS Boston Surf Zone forecast 
These surf conditions will expand to the south for Friday.  Overnight Thursday into Friday the cold front sweeps through the region.  Isolated showers and thunderstorms will break out ahead of the front after midnight Thursday through Friday 3 PM.
WPC Surface Forecast Friday 8 AM
Its a good thing the front does clear by late afternoon as dew points will crank into the low 70's.
18z NAM hires 2 m dew points Friday 2 PM (Image Tropical Tidbits)
Any showers will keep temps down a bit from Thursday but when the sun is shining temps will max out in the mid to upper 80s.  The dew points will make it feel like the low 90s
NWS Max temps Friday (image Weatherbell)
I'm not expecting much in the way of rainfall from any of the storms.  Tomorrow I will post my thoughts on timing.  By the weekend dew points drop as well as temperatures.  Expect low 80's with dew points in the upper 50's on Saturday with sunny skies.  Repeat for sunny although a few stray clouds may pop up.  

Tropical Discussion
Tropical Storm Gaston is experiencing some wind shear so it has yet to become a Hurricane.  I thought it would have by now but it looks like it will have to wait a few days.  First here is the Atlantic surface map.
OPC Tropical Atlantic Surface Analysis
Now here is an infrared satellite image with the current major players.
NOAA GOES-East infrared satellite 615 PM 
Now the same image with the water vapor satellite.  Notice the counter clockwise flow around the upper low heading right into Gaston's path.  This is wind shear.  The upper level winds are strong enough to displace the thunderstorms around Gaston to the east of the center.  In order for a hurricane to be strong the thunderstorms need to be over the top of the center.  Never the less the only impact from Gaston will be strong waves if it can get its act together in a few days because he will track out to sea.
NOAA GOES East Water Vapor Satellite 
Part of that shear looks to be impacting the disturbance near Puerto Rico called 99 L which just means it is a wave or tropical low to be watched.  This is the low that will have a chance to develop into a tropical storm once it clears Hispaniola.  Of course the wave has to survive the trek near the mountainous island (home of Haiti and the Dominican Republic).   Given that a low level center has not formed yet I think it will.  So the 120 hour forecast shows a cone like this.
NHC 120 hour cyclone forecast
By Saturday at 2 PM I expect a storm to be gaining strength in the Bahama's sort of like the recent North American Model run shows.
18z NAM radar and precip 2 PM Saturday (image Tropical Tidbits)
That's about all the actual surface forecasts I will commit to at this point.  But now I think the storm does go into South Florida as a strong Tropical Storm or a weak Hurricane.  I'm hesitant to post what I'm about to say so I will toss about a disclaimer.  I am NOT FORECASTING HURRICANE KATRINA.  However it does remind me of Katrina's first landfall in South Florida as a Category 1 Hurricane.  People forget that Katrina hit near Miami first before it became the monster it did in the Gulf of Mexico.  The track and intensity looks similar to the first part of Katrina, not the second.  Now for the next part of the storm I think it is shifted into the Gulf of Mexico.  High pressure will be in control near the Mid Atlantic coast which will force the storm west.
12z EPS 500 mb height anomaly (image Tropical Tidbits)
After that a trough will move through the Central US leaving a piece behind to capture whatever tropical system is there.  It will be pulled north into the US Gulf Coast.  I can't speculate on strength yet so I won't.  Then by the end of next week the moisture from the system may end up in the Northeast but that's a ways away.  

South Central Florida begins to feel the burnt of the storm Sunday afternoon through Monday.  The Central Gulf Coast will be feel impacts Tuesday and Wednesday if it is able to emerge into the Gulf and not stay over land in Florida.  This is all assuming it forms and doesn't get ripped apart in the Caribbean.  

I'll post another update tomorrow.

-Zack Green

Tuesday, August 23, 2016

Beautiful Wednesday Before Humid Weather Returns

High pressure will remain in control tonight and tomorrow before pushing offshore on Thursday as a weak cold front approaches.  With that cold front comes a chance of showers and thunderstorms especially Friday PM.   Tomorrow will be warmer than today and Thursday will feature a return of the humidity.  Given that it is late August my eyes continue to be focused on tropical weather in the Atlantic.

General Overview
No doubt about it today was one of the top days of the year.  Low humidity, bright sunshine and max temps in the low 80's made for a comfortable day and a great afternoon to be outside.  So who is to blame for such wonderful weather?  High pressure centered over the Mid Atlantic is.  The source region for our air mass in a configuration like this is Southern Canada.
WPC Surface Analysis 2 PM Tuesday
Tonight that high will begin to slide offshore a bit.  Our winds will remain out of the west tonight and tomorrow before taking on a southwest component tomorrow night (they were out of the northwest yesterday and last night).  That slight offshore shift of the high will allow for max temps in the mid to upper 80's tomorrow.
NWS NDFD 2 m max temps Wednesday (image Weatherbell)
Not back to school or fall sports yet and thinking of heading to the beach?  Get up and get gone.  Surf zone forecast looks great for all Southern New England beaches with low rip current risk.
NWS Boston Surf Zone forecast Wednesday 
By tomorrow evening look at the high pressure moving offshore.
WPC Surface Forecast Wednesday 8 PM
The resulting southwest flow leads to a return of dew points in the 60's on Thursday.  There should be a few more clouds on Thursday so temperatures max around 85.  Friday we watch the approach of the cold front and the chance of afternoon showers and thunderstorms.  I don't think we see anything like Sunday night/Monday morning.  For those who were sleeping *pun intended* a EF-1 tornado with 100 mph winds tore through Concord around 345 AM Monday.  Here is some damage.
NWS Boston storm survey Concord, MA
This became the first tornado since June 23, 2015 to hit Massachusetts when a pair of weak twisters impacted Westminster and Wrentham.  Some 230 years ago a tornado hit Sturbridge on this date proving that late summer is still tornado season in Southern New England.
1786 Sturbridge tornado via NWS Boston
Tropical Outlook
The tropics remain active.  Gaston (far right) is nearing Hurricane strength while the middle disturbance continues to slowly organize.
NOAA Atlantic Wide View Rainbow Infrared Satellite image 645 PM
Gaston is on its way to be a powerful open ocean "fish" storm.  In five days the middle system should end up near the Bahama's.  Where it goes from there is a good question.  How strong it gets is also a good question.
NHC Atlantic 5 day tropical disturbance map
As I stated yesterday I believe the storm organizes enough to become named Hermine and it could possibly become a hurricane in the warm water near the Bahama's.  Then will it turn into Florida and the Gulf of Mexico or will it carry north towards the northeast?  Or does it weakly carry out to sea?  I think a track towards Florida and the Eastern Gulf of Mexico before moving north is most likely because of an upper ridge in the Southeast.
NCEP/NOAA relative measures of predictability Tuesday August 30 
This chart shows a decent probability of a ridge near the SE coast in a week.  Now where this sets up exactly will determine the eventual track of this disturbance.  No need to panic I'll keep an eye on it.  We have time!

Five years ago today I was tracking a Hurricane in the Bahama's by the name of Irene.

-Zack Green

Monday, August 22, 2016

What's in a New England Hurricane- Part 2

(This will take the place of the weekly weather take)

For part one see here.

The calendar reads August 22 and right on time the Atlantic Hurricane season has sprung to life.  Tropical Storm Fiona has weakened to a tropical depression but a new tropical depression has formed near the Cabo Verde Islands in the Eastern Atlantic.
5 PM EST Atlantic Basin Overview (National Hurricane Center-NHC)
 Tropical Depression Seven will become Tropical Storm Gaston and then become a Hurricane (and probably a major hurricane) but it should steer clear of land for a long time.  Way down the road, say 10-12 days it may make a turn east of Bermuda before approaching Newfoundland but this is a long way off.  We will have to watch the surf for Labor Day weekend at any rate.  This happens most years because August 20- October 20 is the peak of every season with September 10 as the peak of the peak.
NOAA Hurricane Season Peak
Storms literally form anywhere in late August.  Here is a scatter plot of where storms in the North Atlantic and East Pacific have formed between August 21 and August 31
Storm formation August 21-21 1851-2009 (Image NHC)
Now historically speaking here are the tracks storms typically take in August and September.
August Prevailing Tropical Cyclone Tracks (NOAA/NHC)
September Prevailing Tropical Cyclone Tracks (NOAA/NHC)
I post all of this because the other X in the active tropical cyclone image at the top of the page is forecast to move towards the Bahama's by Saturday.  Any time a tropical cyclone gets near the Bahama's it has a chance to impact the United States, including New England.  Here is the forecast.
NHC 120 Hour Tropical Cyclone formation chances Monday 2 PM 
Will the storm definitely develop?   No it might not.  The American GFS model doesn't really develop the wave.  The EURO model does and it drive a powerful storm into the Gulf of Mexico.  Both solutions are on the table.  I personally believe the lead wave will form and it will get the name Hermine (they should just change that name to Hermoine and get it over with).  Atlantic sea surface temperatures are very warm in the Southwest part of the basin and into the Gulf of Mexico.
2 day average sea surface temperature (image Weatherbell)
Any time a tropical cyclone gets into the Bahama's people in New England have to pay attention.  Its where our last hurricane was born.

Hurricane Bob August 15-19, 1991
Bob first formed on August 15, 1991 near the Bahama's from the remnants of a cold front that pushed off the east coast.  Here are the four panel reanalysis charts at various levels of the atmosphere.  Please look at the top right image.  It shows an upper level high pressure system (ridge) in the NW Atlantic and a upper level low (trough) diving east in the Upper Midwest.
NCEP/NWS/NOAA reanalysis August 16, 1991 8 PM 
Those factors led Bob to move north instead of west or east.  By Monday August 19 Bob was a strong Category 2 Hurricane with winds of 105 MPH racing towards Block Island and Buzzards Bay.  The reanalysis shows why the storm continued north instead of missing out to sea.  It was blocked by that upper ridge.
NCEP/NOAA/NWS reanalysis August 19, 1991
That afternoon Bob made landfall in Block Island and then in Newport.  He drove a 10-15 foot storm surge up into Buzzard's Bay and winds reached 130 MPH in Truro, MA.  Over 2 millions people lost power and 17 people lost their lives.  Over $1 Billion in damage was recorded.  If you remember my post about Connie and Diane the damage was caused by river flooding.  In Bob the damage was from wind and water, but not rainfall.
Hurricane Bob track/rainfall (NWS Boston)
The rain was heavy in Central and Western MA, Eastern CT and SE NH and S ME.  But it wasn't the 15-20 inches in 5 days like the 1955 twins.  Instead the counter clockwise flow around the Hurricane funneled storm surge into Buzzards Bay.  Here is a picture of the Menaahant Yacht Club in East Falmouth, MA courtesy of Doc Taylor before and during Bob
Before Bob
During Bob
Via the NWS Boston 25 year anniversary post
Coastal communities bore the brunt of the storm, with sustained winds between 75 to 100 mph. Peak wind gusts to 125 mph were recorded on Cape Cod in the towns of Brewster and North Truro, as well as in Wethersfield, Connecticut. The highest sustained wind of 100 mph, was recorded in North Truro. Block Island reported sustained winds of 90 mph, with gusts in excess of 105 mph (maximum speed of equipment). Wind gusts to near 100 mph were recorded in Newport and by the Navy Ship Samuel B. Roberts, which was riding out the storm on the east passage between Newport and Jamestown, Rhode Island. Additionally, there were four reports of tornadoes as Bob came ashore. The lowest barometric pressure was recorded by the USS Valdez while in the east passage of Narragansett Bay, with a reading of 28.47 inches. 

Hurricane Bob caused a storm surge of 5 to 8 feet along the Rhode Island shore, but drove a surge of 10 to 15 feet into Buzzards Bay. The Buzzards Bay shore east to Cape Cod was hardest hit. The highest surges, of 12 to 15 feet, were observed in Onset, Bourne, Mashpee and Wareham, at the head of Buzzard's Bay. Cove Road, in Mattapoisett, Massachusetts had 29 of 37 homes destroyed, while Angelica Point, Massachusetts lost 32 of 35 homes along the shore. Boat damage was significant, as many boats were torn from their moorings. Extensive beach erosion occurred along the shore from Westerly, Rhode Island eastward. Some south facing beach locations on Martha's Vineyard and Nantucket islands lost up to 50 feet of beach to erosion.

The storm was really bad in SE coastal New England.  So now we have recapped 2 different years both with devastating effects in Southern New England for different reasons.  Hurricanes have a variety of hazards from coastal flooding to inland flooding to wind damage and tornadoes.  The next post will look at some of the stronger Hurricanes in the Southern New England record.

-Zack Green

Rain Ending As Snow For The Blackstone Valley Tuesday

Tomorrow is Tuesday and surprise, surprise...precipitation is in the forecast.  WBZ went back and found that there has been measurable preci...