Scientific Forecaster Discussion

NWS Discussion
			
				

Area forecast discussion 
National Weather Service Gray ME 
301 am EDT Thursday may 23 2013 


Synopsis... 
a warm front will move north across the area today as low pressure 
tracks along the New England Canadian border. A cold front moves 
through from west to east late today into Friday. Low pressure 
redevelops offshore for the weekend before slowly moving towards 
the Canadian Maritimes. Weak high pressure builds in Monday 
through Wednesday. 


&& 


Near term /through today/... 
shower activity which moved through earlier has exited the 
forecast area. A line of convection in Vermont has been weakening 
steadily as it moves into New Hampshire and a more stable airmass. After 
this activity dissipates this morning there will be a break in 
precipitation until this afternoon when a warm front lifts north 
across the area. The front is now located from Vermont into 
Massachusetts. As the front shifts north warmer air will 
infiltrate southern New Hampshire and southwest Maine. Highs in this area 
will warm into the middle 70s with upper 60s to the north and east of 
the boundary. 


Low level jet increases to 40-50 kts later this afternoon ahead of an 
approaching cold front. This along with increased forcing for 
ascent will increase thunderstorm chances across the area. Not 
expecting any severe weather at this time...just enhanced rainfall 
and run of the mill thunderstorms. 


&& 


Short term /tonight through 6 PM Friday/... 
a sharp upper trough will push the north-northeast-south-southwest oriented cold front 
through the region late tonight into Friday morning...triggering 
widespread showers and thunderstorms. Isentropic lift looks good 
with the 40-50 knots jet in place. 


Precipitable water values jump to near 1.8 inches. A Flood Watch was decided 
against as rainfall has not been as high here as it has been to 
our west. However...the higher terrain may approach flash flood 
guidance in a few basins by tomorrow afternoon. Tonight's lows and 
friday's highs only differ by a few degrees. 


&& 


Long term /Friday night through Wednesday/... 
as the upper level low pressure system continues to migrate 
eastward and moves over the Middle Atlantic States...the attendant 
surface low south of Cape Cod will start to slow down. Northeast 
flow and wrap around moisture will keep precipitation in place 
over the County Warning Area on Saturday. The system becomes pretty much stacked 
over the benchmark by 00z Sunday with little in the way of a break 
from the precipitation over northern New England. The low will 
track across the Gulf of Maine before entering the Canadian 
Maritimes on Monday. Weak high pressure then builds over the 
region for the remainder of the forecast period. 


Seemingly...the models have slowed down the progression of this 
system with just about every run so clearing the Gulf of Maine on 
Monday might be a bit optimistic. We will have to watch the next 
few runs to see if the system looks like it will slow even more 
than it already has. 


&& 


Aviation /07z Thursday through Monday/... 
short term...LIFR/IFR conditions this morning with visibilities 
and ceilings improving by late morning. Gusty south winds will 
develop as a warm front lifts north. Showers and thunderstorms 
will develop later this afternoon and evening keeping conditions 
low. Visibilities and ceilings will drop further tonight. 


Long term... 
LIFR/IFR conditions will prevail for most of the long term as a 
slow moving low pressure system moves across the region. 


&& 


Marine... 
short term...Small Craft Advisory was extended through Saturday 
morning with winds and waves staying above criteria. 


Long term...as low pressure develops and moves across the Gulf of 
Maine...expect Small Craft Advisory for most of the weekend. 
Persistent easterly flow will help keep seas above Small Craft Advisory criteria. 


&& 


Fire weather... 
fire weather concerns remain low with recent rains keeping fuels 
moist. Rain is expected areawide through the weekend. 


&& 


Gyx watches/warnings/advisories... 
ME...none. 
New Hampshire...none. 
Marine...Small Craft Advisory from noon today to 8 am EDT Saturday for 
anz150>154. 


&& 


$$ 


Hanes/pohl