Scientific Forecaster Discussion

NWS Discussion
			
				

Area forecast discussion 
National Weather Service Taunton Massachusetts 
404 PM EDT Wednesday Jun 19 2013 


Synopsis... 
high pressure overhead will provide beautiful weather 
tonight and Thursday with comfortable humidity levels. The high 
moves offshore Friday and begins a trend toward warmer and more 
humid weather into this weekend and next week. The vast majority of 
the time will be dry...but will likely deal with at least a few 
bouts of showers/thunderstorms. 


&& 


Near term /until 6 am Thursday morning/... 
diurnal cumulus clouds will dissipate this evening with the loss of 
daytime heating. Otherwise...high pressure builds in from the west 
resulting in mostly clear skies and diminishing wind. Given the dry 
airmass in place...the stage is set for a good night of radiational 
cooling. Low temperatures will be cool for this time of year...with 
readings well down into the 40s across the outlying locations. The 
urban centers of Boston/Providence will be the mild spots with 
overnight lows in the lower to middle 50s. 


&& 


Short term /6 am Thursday morning through Thursday night/... 
Thursday... 
high pressure overhead will result in another beautiful 
day for the latter half of June. Plenty of sunshine will allow 
temperatures to recover rather quickly after a cool start. High temperatures will 
be mainly in the upper 70s to around 80 with comfortable humidity 
levels. 


Thursday night... 
another quiet night in store for the region with 
high pressure in control. The airmass modifies some so low temperatures 
will not be quite as cool as tonight. Low temperatures will mainly be in 
the 50s. 


&& 


Long term /Friday through Wednesday/... 
highlights... 
* high pressure brings quiet weather Friday 
* high pressure S of southern New England brings warm...humid conditions this weekend 
* showers and thunderstorms possible Saturday 


There is good general agreement amongst the models through much of 
the long term. There are some model discrepancies regarding the 
strength and extent of an upper level ridge over the eastern U.S. 
Into early next week. Ultimately this will affect the weather in 
this area mainly in where and when showers and thunderstorms are 
able to develop. The consensus is with the European model (ecmwf) and the upper 
level ridge over the southeast Continental U.S. Gradually building northward into the 
Ohio Valley by Saturday then sinking back south early next week. 
There are also some discrepancies in how quickly the ridge breaks 
down and allows an upper trough to move through the northeast. The 
European model (ecmwf) keeps enough ridging over southern New England to keep the 
trough to the north in southeastern Canada while the GFS breaks it 
down...allowing the trough to move over New England. 


Am expecting fairly quiet weather overall with more Summer like 
temperatures and a few humid days thrown in there as well. There is 
potential for showers and thunderstorms each day in the long term 
with plenty of moisture and instability available. The one missing 
ingredient is a well-defined trigger. While there is potential each 
day...the best days for showers and thunderstorms are Monday and 
Wednesday with a pre-frontal trough and a cold front...respectively. 
Activity on other days will depend on the timing of shortwaves 
moving over the upper ridge. 


&& 


Aviation /20z Wednesday through Monday/... 
forecaster confidence levels... 


Low...less than 30 percent. 
Moderate...30 to 60 percent. 
High...greater than 60 percent. 


Near term /through Thursday night/...high confidence. 


VFR condition expected right through Thursday night. Isolated 
patchy ground fog possible very late tonight and again late Thursday 
night...but areal coverage will remain very limited and not expected 
to affect any of our terminals. 


Kbos terminal...high confidence in VFR. Sea breezes end between 01z 
and 03z this evening. Southeast sea breezes likely re-develops late 
Thursday morning or afternoon for a few hours. 


Kbdl terminal...high confidence in taf. 


Outlook...Friday through Monday... 


Moderate confidence. Mainly VFR. There is a low probability of 
showers and thunderstorms and accompanying MVFR/IFR conditions each 
aftn/eve. 


&& 


Marine... 
forecaster confidence levels... 


Low...less than 30 percent. 
Moderate...30 to 60 percent. 
High...greater than 60 percent. 


Short term /through Thursday night/...high confidence. 


Left over 3 to 5 foot seas across our southern Atlantic waters will 
diminish this evening. Will let Small Craft Advisory expire for these waters at 7 
PM. Otherwise...high pressure overhead will keep winds/seas below 
Small Craft Advisory thresholds right through Thursday night. 


Outlook...Friday through Monday... 


High confidence. 


Quiet boating weather expected through Monday with high pressure 
near or over the waters. There is a low probability of showers and 
thunderstorms each afternoon/evening that may limit visibilities on the 
waters. Seas increase Monday night as a weak cold front or pre- 
frontal trough moves across the waters. 


&& 


Hydrology... 
concerning river flooding...the Charles at Dover remains just 
above flood stage. Latest guidance indicates that this river will 
remain in minor flood through Friday afternoon. 


&& 


Climate... 
here is a listing of record low temperatures for 
Thursday. Low temperatures tonight will not quite make these 
numbers...although it will be within a few degrees at 
Hartford /Bradley International Airport/. 


Boston... 47 in 1918 
Hartford... 45 in 1918 
Providence... 45 in 1918 
Worcester... 37 in 1926 


&& 


Box watches/warnings/advisories... 
CT...none. 
Massachusetts...none. 
New Hampshire...none. 
Rhode Island...none. 
Marine...Small Craft Advisory until 7 PM EDT this evening for 
anz254>256. 


&& 


$$ 
Synopsis...Frank/rlg 
near term...Frank 
short term...Frank 
long term...rlg 
aviation...Frank/rlg 
marine...Frank/rlg 
hydrology...staff 
climate...staff