Thursday, June 27, 2013

Flash Flood Watch Issued Today & Friday

A anomalous low pressure system will cut up through the Appalachians keeping most of New England in a wet pattern.  While some of the storms are bound to be hit or miss the air mass is very tropical and the ground is saturated.  Therefore the National Weather Service in Taunton has issued a Flash Flood Watch for all of Southern New England (except Cape and Islands)

NWS Boston (top) and NWS Portland (bot) Hazards
A stationary boundary to the north will help usher multiple storms into New England.  Surface low pressure is developing in the Ohio Valley.  
WPC surface analysis 5 am
At the upper levels the low has not "cut off" as of yet but that will happen later today/tonight.  As of this morning a shortwave was pressing through the Ohio Valley
06z NAM hires 500 mb heights 8 am Thur (image weatherbell)
Here is the amount of moisture available in the air.  We call this Precipitable Water, or PWATS
SPC 10z PWAT Mesoanalysis
A batch of 2 inch PWATS is just offshore and moving NE.  This will be the main threat with any embedded thunderstorms along with frequent lightning.  Winds and hail appear to be a marginal at best threat today in Southern New England.  The Storm Prediction Center (SPC) likes a severe threat in the Mid Atlantic
SPC Day 1 Thunderstorm Outlook
Depending on how much sun light can break through portions of Southwest New England may be in on the severe weather action.  By tonight the front will be sagging south towards the MA/NH/VT border and perhaps to Worcester.  At the same time the low pressure system will be moving through PA and NE into NY state
WPC surface forecast 8 PM 
Tomorrow morning the rain will be heavy an intense.  Here is a snapshot at the potential PWATS at 10 am
06z NAM hires PWAT 10 am Fri (image weatherbell)
With a surface chart like this
WPC surface forecast 8 am Fri
One will expect inches of rain in the Northeast tomorrow.  The WPC is forecasting between 2-3 inches of rain through Sunday morning
WPC Day 1-3 total precipitation
Current temperatures (5 am)
5 am 2 m temps (image weatherbell)
A mild and muggy start in Southern New England.  The cold front is draped through Eastern NH and ME.  Today Southern New England warms while Northern New England does not
06z NAM hires 2 m temps 4 PM (image weatherbell)
With temps in the low to mid 80s in the CT River Valley it will be interesting to watch storms firing in the high grounds of the Berkshires. Tonight the boundary will push to the MA/CT border and perhaps even to Hartford.  Temps will be in the 50's on the North side, upper 60's on the south side
06z NAM hires 2 m temps 6 am (image weatherbell)
Finally high temperatures rise into the 70's tomorrow
06z NAM hires 2 m temp 3 PM Fri (image weatherbell)
All for now, talk to you tomorrow


Wednesday, June 26, 2013

Muggy with Severe Thunderstorms

Although today will not be as warm as Monday and Tuesday the dew points will remain in the mid to upper 60's across most of Southern New England and thunderstorms will be possible again.  No this is not a recording and the thunderstorms will be more numerous as there is a trigger for the storms today.
SPC Day 1 Thunderstorm Outlook
The main threat will be damaging winds ( > 58 mph)
SPC Day 1 Severe Wind Outlook
Short Term Forecast/Observations
Temperatures are off to rocking start with the majority of the region south of Worcester already in the 70's
5 am 2 m temps (image weatherbell)
The rest of Southern New England is still in the upper 60's.  This morning it is going to be tough to rely on the models as they are forecasting a back door cold front which never really goes well.  The cold front should back across the Maine/NH seacoast during the midday hours.  How far it gets in MA is important as to where the best severe thunderstorm potential develops.  Visible satellite shows some broken clouds over SNE
GOES_East NWS Boston Visible Satellite 545 am
In areas in which the clouds and fog burn off quickly this will also help to destabilize the atmosphere.  Around noon areas south of Rt. 2 in MA should be in the low 80's with dew points in the mid to upper 60's
06z NAM hires 2 m temps 12 PM (image weatherbell)
Dew points around 2-3 PM
06z NAM hires 2 m dew points 3 PM (image weatherbell)
A boundary currently drapped in Northern New England (see current temps and look at Northern Maine) will progress south during the morning and afternoon.  A surface low should develop and park itself near the Southern Maine shore
WPC Surface forecast 2 PM
The front will be pushed back tonight into New Hampshire and Maine.  Lows there will drop to around 60 while Southern New England stays steamy.  An upper level wave will work over New England tomorrow, from the Great Lakes
00z NAM 500 mb heights 8 am Thur (image weatherbell)
The surface reflection of this pattern
WPC Surface forecast 8 am Thur 
With a front trying to attack from the east this sets up another forecasting headache.  One model suggests that it is 85 in Nashua, NH while it is 67 in York, ME
06z NAM hires 2 m temps 2 PM Thur (image weatherbell)
The SPC is less impressed with the thunderstorm threat tomorrow yet still notes a chance for a severe storm albeit low.
SPC Day 2 Thunderstorm Outlook
Thursday evening a stationary boundary will exist near the MA Pike.  
WPC Surface Forecast 8 PM Thur 
The set up for Friday looks more ominous in terms of a severe weather threat.  Low pressure will deepen in New York State as low pressure in the upper levels cuts off.  This will lead to rounds of showers and thunderstorms. With clouds holding the temperatures down Friday looks like it will struggle to get to 80.  That won't matter in Southern New England.  First check out the surface forecast
WPC Surface Forecast 8 am Fri
Here are the dew points at 2 PM
06z NAM hires 2 m dew point 2 PM Fri (image weatherbell)
The total precipitation throughout the next 3 days (through Saturday 8 am) is impressive.
WPC Day 1-3 Precipitation Outlook
This will add to June's rainfall tab

This cold front will be extremely slow moving.  Saturday morning
WPC Day 3 Surface Forecast Sat 8 am
At the 500 mb level a deep trough will be in place over the east while sharp ridging is present in the west.  This will lead to some record heat out west (though most of the temperature stations out west were built after the warm 1930's and 1950's)
00z EURO 500 mb heights Sat 8 PM (image weatherbell)
Sunday is similar except the front will possibly stall out over the coast.  This will need to be watched as waves of low pressure can sometimes ride along the boundary flooding the areas it sits over.  Here is the weekend rainfall estimate (conservative  at this range)
WPC Day 4-5 Precipitation Forecast
Temperatures each day are in the upper 70's/low 80's.  So while the pattern is similar to summer of 09 in terms of rain it will not match the cold temperatures of that summer.  Have a good day...hump day!

Tuesday, June 25, 2013

More Heat, Humidity, and Thunderstorms Today

Oppressive heat and humidity will continue to dominate our weather in New England.  With these conditions comes a risk of thunderstorms some of which may be severe.  There were quite a few severe weather reports yesterday in the northeast
SPC Storm Reports 6/24/13
The threat today should be slightly further north but several areas will get hit again today especially in Southern VT and NH.  The NH and ME seacoast have been routinely pounded by thunderstorms in the past few weeks
SPC Day 1 Thunderstorm Outlook
Damaging winds and large hail are the biggest things to watch.  Current temperatures are in the 60's
2 m temp 5 am (image NCEP)
Even nastier are dew points already in the low to mid 60's
2 m Dew Point 5 am (image NCEP)
Temperatures will quickly rise into the 80's and low 90's this afternoon
00z NAM hires 2 m temps 3 pm (image weatherbell)
The simulated radar around 6 PM shows a nice cluster of thunderstorms in Western New England.
00z NAM hires simulated radar
Will get back to forecasting the medium range tomorrow have a good Tuesday.

Monday, June 24, 2013

Hot and Humid Today

Hot and Humid weather will dominate over the next few days.  Brief forecast today
2 m temps 5 am (image weatherbell)
It is a mild start with temperatures already in the low 70's in a lot of places.  Temperatures are forecast to rise into the low 90's
06z NAM hires 2 m temps 3 PM (image weatherbell)
Dew points will be in the low to mid 70's
06z NAM hires 2 m dew points 2 pm (image weatherbell)
There is a slight chance of thunderstorms this afternoon
SPC Day 1 Thunderstorm Outlook
Any thunderstorm activity will blossom around 2 PM.  Western New England has the greatest chance at seeing something severe.  There will be a lot of fuel to work with, just not much of a trigger.  There may be a weak trough extending from low pressure in Quebec so I'll watch the radar.  Mild night tonight and temperatures will soar back into the upper 80's low 90's tomorrow.  There is another threat of thunderstorms tomorrow.  Have a good Monday

Friday, June 21, 2013

Happy Summer!

Summer officially began at 104 am this morning and there is some hot and humid weather in the forecast.  It does not appear to be a permanent shift towards hot, humid, and relatively dry air.  However the weekend looks great in Southern New England despite a small chance at shower tomorrow afternoon.  Stay south this weekend as the rain will be falling in Northern New England in association with a frontal boundary.

Short Term Forecast/Observations
A cold front is present in Southern Ontario
WPC Surface Analysis 5 am
Behind the front temperatures are very chilly this morning but here in Southern New England most are running in the mid to upper 50's
09z RAP 2 m temp 5 am (image weatherbell)
Here is the current 500 mb set up
06z NAM 500 mb heights 5 am (image weatherbell)
This ridge will continue to spread towards the east coast.  Sunday and Monday look like the best bets to be near 90.  Today however temperatures climb into the low and mid 80's.  Urban centers and valleys are in the mid 80's, rural and higher elevations will be in the lower 80's.
06z NAM hires 2 m temps 4 pm (image weatherbell)
Overnight low temperatures stay in the 60's which will help set the stage for another warm Saturday although I think most stay below 90.  Springfield and Hartford and the rest of Southwestern New England are the best bets to make a run at 90.  The surface chart for tomorrow shows high pressure still in control
WPC surface forecast 8 am Sat
Here are the afternoon temperatures
06z NAM hires 2 m temps 2 pm Sat (image weatherbell)
Overnight lows on Saturday will only fall into the mid 60's.  By 8 am it will already be in the 70's again.  By noon we will be in the low to mid 80's and by 2 pm many will be over 90
06z NAM hires 2 m temps 2 pm Sun (image weatherbell)
The dew points will also rise to near 70.  This will make thunderstorms possible, but will also make conditions oppressive 
06z NAM hires 2 m dew points 2 pm Sun (image weatherbell)
BUT there is not a real trigger for a widespread severe weather outbreak as long as this cold front remains in Canada.  
WPC surface forecast 8 am Sun
Have a good Friday and Happy Summer

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