Thursday, June 30, 2016

Friday Night Fireworks- Man Made or Mother Nature?

The Storm Prediction Center has issued a marginal risk for severe storms across Southeastern New England tonight
SPC Day 1 Severe Thunderstorm Outlook
The threat is greater to our west in the Mid Atlantic.  By 8 PM a squall line should form in Western New England.  Guidance suggests this stays to our north and west through 10 PM.
09z HRRR simulated radar 8 PM (image College of Dupage NeXLaB wxcenter)
This line of storms will be capable of strong winds and frequent lightning.  Next update to be posted this afternoon.

Previous discussion below

Most of the holiday weekend looks spectacular in Southern New England.  The only question is tomorrow night.  The Worcester fireworks have been postponed to Saturday already.  Let's take a quick look at this although I will have to update tomorrow as radar trends become clear.

The current surface chart looks like this
WPC surface analysis 5 PM
By tomorrow evening the cold front will be in upstate New York as high pressure descends into the Midwest.
WPC Surface forecast 8 PM Friday
As of 2 PM some thunderstorms will fire in Eastern NY and Western New England.  Although there is some green on this simulated radar image in Central MA it will likely be dry or just a small shower
18z NAM hires simulated radar 2 PM Friday (image Tropical Tidbits)
By 9 PM this model is showing most of the energy west of the Blackstone Valley and Eastern SNE.
18z NAM hires simulated radar 9 PM Friday (Image Tropical Tidbits)
The total precipitation chart as of 11 PM shows no accumulation from Worcester County on east
18z NAM hires accumulated precipitation through 11 PM Friday (image Tropical Tidbits)
Now let me caution that this is just 1 model and it has been known to miss things.  The Canadian regional high resolution model sends a strong line of thunderstorms through the region
18z RGEM mslp/precip 11 PM Friday (image Tropical Tidbits)
I would avoid cancelling any plans as of tonight.  I will keep updating this blog with the latest information as it becomes available.  A lot of storms have fallen apart as they approach Central MA during this dry stretch.  But then there are storms like yesterday morning in which an inch of rain fell in about 45 minutes.  You can't blast fireworks off in that or expect spectators to sit outside as strong winds and dangerous lightning moves through.  I do favor the American model at this time because I think most of the activity will be in Western/Northern New England but I can certainly see how Southern New England gets in on the action.

Cheers- Zack Green

Tuesday, June 28, 2016

Tuesday June 28, 2016

Slow moving AM rain showers will all but dissipate by 8 AM.  The rest of the day will be mostly cloudy with some breaks of sun.  A cold front will cross the region tonight resulting in overnight showers/thunderstorms.  Southern New England will be in the "warm sector" today which means it will be quite humid this afternoon.

General Overview
Here is the cold front slowly moving towards New England
WPC Surface Analysis 2 AM
The cold front will touch off some severe thunderstorms in Eastern PA through upstate NY into VT
SPC Severe Weather Outlook Tuesday 
Some of these storms may impact Western MA/CT but they will form after 7 PM.  Here is the 7 PM radar snapshot
08z HRRR Simulated radar 7 PM tues (image College of Dupage WxCenter)
Temperatures today reach the upper 70's/low 80's
NWS NDFD max temp forecast Tuesday (image Weatherbell)
Dew points will rise into the mid 60's.  These conditions stay around tonight which is our best chance for good rain.  Optimistically we could squeeze out over a 0.5" tonight (more to our North and West)
WPC Day 1-2 precip forecast 
The front slowly clears tomorrow.  A few showers will be possible but overall it will be warmer and nicer than today.  High pressure takes control Thursday.  I'll post on the long weekend tomorrow.

-Zack Green

Monday, June 20, 2016

Some Needed Precipitation Tonight

My belief is that most of Tuesday will be dry.  There will be some needed rain overnight but with the lawns as dry as they are people will still need to water this evening and tomorrow.  Let's take a quick look at this.

WPC Surface Analysis 5 PM 
A cold front sweeping through Ontario and the Great Lakes will cross New England tomorrow.  While the actual passage of the front will be dry an isolated shower is possible.  The biggest threat will be ahead of this line after midnight across all of SNE.  Latest high resolution radar trends bring the thunderstorms into Central MA and the Blackstone Valley around 3-6 AM.
22z HRRR simulated radar Tuesday 4 AM (image NeXLaB Wx center college of dupage)
Precipitation totals will be 0.25-0.4 inches max and that is only in the embedded thunderstorms. Most of us see less than 0.1".  Frequent lightning and gusty winds will accompany the downpours so don't be alarmed when you wake up early tomorrow morning.  By 9 AM most of the precipitation will clear the South Coast.
22z HRRR simulated radar Tuesday 9 AM (image College of Dupage NeXLab wx center)
Drought conditions are growing again across the region just as the gypsie moths eat away at our trees.  It certainly is odd to see the bare trees on June 20.
US Drought Monitor June 14. 2016
Temperatures climb into the mid 80's tomorrows in Eastern MA, the Blackstone Valley and Western MA.
NWS NDFD max temperature forecast Tuesday (image Weatherbell)
Early glance at the weekend looks great.  Maybe some rain Thursday night but the drought will get worse this week.  No end in sight to the dry spell that is now over a year old.  Often times a tropical system can wipe out an entire deficit in one storm.  While we will likely have to wait until August before something like that happens there is a Tropical Storm in the Southern Gulf of Mexico that will make landfall in Mexico.  The storm is weak but it marks the earliest occurrence of the 4th tropical storm on record.  This is Danielle
NOAA GOES_floater Rainbow IR satellite 1245 PM
She has now made landfall which is probably good.  She was looking really nice this afternoon on satellite.  I love tropical meteorology so the action is welcome after several  below average seasons.   As for the weekend I am thinking the Bermuda high is in control.  Warm and dry- perfect for the pool and grill (or lake, ocean).
WPC Surface Forecast Saturday 8 AM
-Zack Green

Friday, June 10, 2016

Challenging Saturday Forecast

A warm front will lift through Southern New England on Saturday followed by a cold front Saturday night.  At the same time a complex of thunderstorms currently in the Great Lakes may survive the trip across NY/PA and enter Southern New England tomorrow afternoon.  High resolution computer guidance suggests this moves across MA/RI/CT but climatology suggests it stays south.  Let's break it down.

Current Conditions
Here is the current surface chart.  The warm front is in red across MI, PA and VA.  The current severe weather complex is associated with the low pressure across MN and WI
WPC Surface Analysis 5 PM
This evening is fine- maybe a bit cool for June 10 but very comfortable.  Meanwhile here is the Great Lakes regional radar
NWS Great Lakes regional radar
This complex of storm will strengthen and sustain itself overnight.   By noon time guidance suggests it is ready to enter Southern New England.
18z NAM hires Simulated Radar 12 PM (image College of Dupage NeXLaB)
The surface analysis an hour later shows the warm front ready to advance through New England
WPC surface analysis 1 PM Saturday
I do believe this complex stays alive- but will it get into Southern New England?  I think so but I cannot say where this tracks until tomorrow.  The timing will be roughly 12-4 PM and the complex will feature heavy rain, gusty winds and lightning.   The Storm Prediction Center has Central/Western MA, RI and CT in a risk of severe thunderstorms
SPC Saturday Severe Thunderstorm Outlook
Next we have to consider the trailing cold front Saturday night.  There is the chance for strong storms as the cold front moves through Saturday night.  It is early in the season for nocturnal New England thunderstorms so I will evaluate this tomorrow.  I apologize that this "forecast" is a lot of "I believe" and "chance" but until 12 hours ago it looked like the weekend would be OK save for Saturday night storms.  Perhaps as a forecaster we have been spoiled by technology and this is one of the times that I have to actually forecast so here goes.

Saturday 12-4 PM - Rain with embedded thunderstorms.

Saturday 4-9 PM - Isolated showers/thunderstorms.  Thunderstorms more likely in CT/RI.

Saturday 9 PM - Sunday 5 AM - 50% chance of thunderstorms- will have to refine this later.  Please be aware of the possibility.

-Zack Green

Monday, June 6, 2016

UPDATE- 5 AM Strong Thunderstorms Possible Tuesday

A few showers are moving into Southwest Worcester County as of the 5 AM hour.  A larger batch of showers is tracking through Western MA into Vermont and NH.  It appears these storms continue to trek into Northern New England and dissipate around 10-11 AM.
Boston radar 451 AM (RadarScope Pro)

In its wake skies will clear the atmosphere will destabilize.  The Storm Prediction Center has upgraded Southern New England to a slight risk.
SPC Severe Weather Outlook Tuesday
High resolution guidance is favoring action in Eastern MA.  There are some limiting factors that should keep the region out of a widespread severe weather outbreak but any thunderstorms will have the potential for hail and gusty to damaging winds.
8z HRRR Simulated Radar 4 PM (image College of Dupage NeXLaB)

Keep an eye on the dew points today.  I will update a new post as needed with severe watches/warnings.

-Zack Green

Previous discussion below

An approaching cold front with strong low pressure in Quebec will approach Southern New England on Tuesday.  Initial showers and thunderstorms will form overnight through tomorrow morning.  If these clear quickly tomorrow morning the atmosphere will destabilize for the afternoon.  At that point strong to severe thunderstorms will form throughout New England.  Primary hazards will be hail and damaging winds although an isolated tornado is possible.

General Overview
Here is the projected surface chart tomorrow 8 AM
WPC Surface Forecast Tuesday 8 AM
Some activity will form overnight into the morning hours.  Here is one high resolution computer model radar forecast at 6 AM
18z NAM Hires simulated radar 6 AM Tuesday (Image College of Dupage NeXLaB)
Not everyone will get wet.  These storms will be scattered.  These should clear by 9 AM and if so we will have a good shot at seeing strong thunderstorms after 2 PM.  Here is the surface chart at 2 PM
WPC Surface Forecast Tuesday 2 PM
You can see Tropical Storm Colin off the NC coast at this time.  The approaching cold front that will help produce the severe weather will also force Colin out to sea.  This is good because as Colin becomes a non tropical system it will strengthen and become a fairly strong cyclone.  As the front kicks out Colin cold air in the upper levels of the atmosphere will help allow for strong winds and hail in anything thunderstorms.
18z NAM Hires Simulated Radar 3 PM Tuesday
This post will be updated tomorrow to really hone in on the hazards but if you have to be outside tomorrow afternoon please keep an eye to the sky.  High temperatures should reach the low 80's with dew points in the low to mid 60's- a tropical air mass for part of the day.

-Zack Green

Biggest Snow Storm Of The Season Heads To Impact Region Tonight

The National Weather Service (NWS) in Norton, MA has issued a * Winter Storm Warning * from 7 PM tonight until 10 AM Wednesday.  A widesprea...