990 
fxus61 kcar 210816 
afdcar 


Area forecast discussion 
National Weather Service Caribou ME 
416 am EDT sun Mar 21 2010 


Synopsis... 
high pressure will move east today then a weak disturbance will 
quickly cross the state later today into tonight. Strong low 
pressure will track just south of the region later Monday through 
Wednesday. 
&& 


Near term /through tonight/... 
frontal boundary just S of the forecast area west/ a shallow dome of cold air and 
hgh pressure across northern areas at this time... large temperature diffs currently exist across 
the area west/ temperatures ranging from upper teens north to around 40 S. Hgh 
pressure centered over southern Quebec at this time expeceted to quickly shift east of the forecast area 
this am as a fast moving upper disturbance in its wake swings 
across the region and brings a quick moving area of overrunning 
precipitation across mainly central areas later today into tonight. Will 
carry likely probability of precipitation across central areas west/ chance probability of precipitation southern and northern 
areas then probability of precipitation quickly drop off to none northwest and low chance southeast by Erly 
Monday. Temperatures cold enough across the area for a mix of light rain and 
snow later today changing to a period of light snow Erly tonight then 
ending after mdngt... fast moving nature of this disturbance and 
limited moisture suggest only an inch or two of snow at best 
across central and east central areas. Temperatures today expeceted to range from 
the middle 30s far northwest to middle 40s downeast...significantly cooler than 
yesterday with the entire forecast area north of the frontal boundary. 
&& 


Short term /Monday through Tuesday/... 
shortwave drags a cold front across the northern portions of the 
state during Monday...with a reinforcing shot of cold and dry air 
associated with high pressure in Quebec. The front will stall 
along the coast and focus precipitation Monday afternoon and night along 
this boundary in coastal regions. Should be mostly in the form of 
rain as critical thicknesses look a bit high. Moisture will 
continue streaming northward along this boundary Monday night with 
steady precipitation in coastal regions. This precipitation will spread steadily 
northward during Tuesday as low pressure moves from the Ohio Valley 
to near Boston by Tuesday evening. P-type will remain rain in 
southern portions of the forecast area but mixed precipitation looks likely in 
central and northern Maine. Sleet appears to be the more 
predominant frozen p-type rather than snow due to warm air aloft 
above a fairly deep cold layer induced by the east flow around the 
Quebec high. Boundary layer temperatures in the middle 30s will also help 
reduce chances of any accumulating snow. 


Rainfall during this period...especially Tuesday has the potential 
reach one to two inches in coastal counties. Am not especially 
concerned about flooding due to recent dryness...lack of snow 
cover...and recent warm temperatures. 


Coastal winds during Tuesday could also gust over 40 miles per hour as the storm 
develops in southern New England. A Wind Advisory will have to be 
considered as the event gets closer. 
&& 


Long term /Tuesday night through Saturday/... 
guidance increasing pointing towards the surface low tracking into the 
Gulf of Maine Tuesday night...maintaining a mixed bag of precipitation in 
central and northern Maine. Sleet still seems the more likely 
threat in these areas. Precipitation should wind down during Wednesday as the low 
tracks to Nova Scotia and colder air will allow a changeover to 
snow across the forecast area during the day with no significant 
accumulations foreseen at this time...but critical thicknesses are not too 
far from snow criteria Tuesday night when the heavier precipitation falls...so the 
situation could change with subsequent model runs. Snow tapers off 
in the north Wednesday night with strong cold air advection Wednesday night into Thursday. Have 
dropped off temperatures a bit from previous packages for Thursday highs. 


After high pressure moves across the forecast area Thursday...an Arctic blast 
arrives Friday with the coldest air since very early February for 
the state. Highs look to be in the upper teens to twenties for Friday 
and Sat with cold northwest winds. Lows in the single digits to teens 
also appear a reasonable bet. This airmass may seem extra cold 
based on the record warmth of the past week. 
&& 


Aviation /07z Sunday through Thursday/... 
near term: mainly VFR conds far northern taf sites and kbhb today and 
tonight west/ best chances for MVFR later today into tonight in light snow/mixed 
precipitation khul and kbgr. 


Short term: expect MVFR to IFR for southern taf sites bgr and bhb 
Monday with VFR all points north of bgr likely. The MVFR/IFR will 
persist Monday night in the south and gradually spread northward 
later in the night toward hul. For tues, most of the state should 
be predominately IFR in rain with sleet possible for 
hul...pqi...car...fve and gnr. These conditions will persist into 
Tuesday night. Wednesday will become VFR at bgr and bhb while MVFR will be 
the predominant condition north with occasional IFR in snow. 
&& 


Marine... 
near term: winds/seas expeceted to remain below Small Craft Advisory levels through tonight... 


Short term: conditions will deteriorate to gale early Tuesday am and 
persist through most of Tuesday night. Small Craft Advisory conditions likely to persist 
through the week following the gale. 
&& 


Car watches/warnings/advisories... 
ME...none. 
Marine...gale watch from Tuesday morning through late Tuesday night for 
anz050>052. 


&& 


$$ 
Near term...khw 
short term...mwalker 
long term...mwalker 
aviation...khw 
marine...khw/mwalker