039 
fxus61 kgyx 220706 
afdgyx 


Area forecast discussion 
National Weather Service Gray ME 
306 am EDT Monday Mar 22 2010 


Synopsis... 
low pressure will slowly migrate NE to the Gulf of ME over the next 
few days. Weak high pressure will build in behind the system on Thursday. A 
strong cold front will cross New England on Friday. 


&& 


Near term /today and tonight/... 
cut-off area of low pressure will meander to the NE over the next 
couple days. Details with such systems...as always...remain 
uncertain. 


00z model suite in relatively good agreement in the short term 
bringing the surface low near the appalachian spine today. By 
tonight...a secondary area of low pressure will form east of New Jersey. This track 
will allow for a relatively prolonged period of rain...begining 
during the day today and continuing into the long range. 


System already taping moisture from the Gulf of mex and near the 
Bahamas. Expect conveyour belt of precipitation in increasing precipitable 
water values to pump heavy rain into much of our forecast area. 
Most vulnerable region for potential flooding will be over 
southern areas...which received the most precipitation from the last couple 
storms (see Hydro disc below). 


There is the potential for pockets of freezing rain and sleet 
tonight per latest model soundings over northernmost portions of the 
forecast area. Otherwise...it appears the precipitation will be mainly in 
the form of rain across the region in the short term. 


Mav/met MOS in good agreement and xcptd. 


Winds...likely to be stronger than models are currently suggesting 
from the NE. 


Quantitative precipitation forecast...running high this run...in the 2-3 inch range over southern 
portions of the forecast area. Expct there to be locally higher totals 
in reasonably strong and persistent southeast flow just above the surface. 


&& 


Long term /Tuesday through Sunday/... 
upper low moves from Delaware-Maryland-Virginia Tuesday morning northeastward into the Gulf of 
Maine Tuesday night. Heaviest rains will be during the day Tuesday and 
went with 100 percent probability of precipitation since its now a certainty. Total quantitative precipitation forecast 
should be in the 2-3 inch range. The models all agree on moving 
the center of the surface/upper low rapidly northeastward into the Maritimes 
later Tuesday night and Wednesday allowing downsloping winds in the storms 
wake. The precipitation should taper to scattered showers late Tuesday night and Wednesday. 
Ptype will be a problem in the mountains and foothills where a 
changeover to snow is expected with several inches of snow possible Tuesday 
and Tuesday night. Strong cold air advection is expected in the storms wake Wednesday so 
colder temperatures expected for highs even with a downsloping wind. In 
the mountains scattered snow showers are expected. On Thursday afternoon and evening a much 
stronger Arctic front moves through the area with scattered snow showers amend a 
shot of much colder air. Accepted gmos temperatures for Thursday and beyond. 
Over the weekend models try to carve out a long wave trough over the 
Great Lakes allowing moisture to spill into the region later Sunday. 


&& 


Aviation /06z Monday through Friday/... 
short term...ceilings will continue to gradually lower today and 
tonight into IFR status. Patchy fog will develop as well. 


Long term...IFR to LIFR conds expected Tuesday into Tuesday night then 
becoming VFR late Tuesday night and Wednesday except briefly lower in any scattered 
showers. On Thursday an Arctic frontal passage Thursday afternoon and evening will produce scattered 
snow showers lowering conds to MVFR or even IFR. Behind the frontal passage strong 
northwesterly winds Thursday night and Friday with VFR conds. 
&& 


Marine... 
short term...expect minimal gale conditions for the outer waters. 
Hence...a Gale Warning has been issued for those areas. Please 
note...consensus forecast is above model guidance values with this 
preferred track for increasing coastal winds. Small Craft Advisory elsewhere. 


Long term...a period of east-northeasterly gale force winds is expected Tuesday 
ahead of an approaching and deepening coastal low that moves northeastward 
from Delaware-Maryland-Virginia. Guidance appears to be considerable too low. The surface 
low passes over the waters by Tuesday evening so winds will drop off 
abrubtly and then shift to northwesterly as the surface low tracks northeastward into 
the Maritimes later Tuesday night and Wednesday. May need gales late Wednesday or 
Wednesday night for the gusty northwesterly cold air advection winds over the waters....and again 
possibly late Thursday night and Friday. 


&& 


Hydrology... 
a very moist and persistent southeast flow (just above the surface) will 
develop with slow moving cut-off low. Expect rainfall to be in the 
2-3 inch range over southern locations with locally higher amts possible. 
This would place some small rivers and streams over southern areas into 
flood as guidance suggests around 2.5" of rain would cause prblms. 
Hence...a Flood Watch has been issued for this region. Southern 
areas are also the regions which were hit hard by the last 
storm...particulary York County and portions S and west. 


Further to the north...rain has not been an issue with the last couple 
storms. Future shifts will need to monitor this region. At this 
time...not anticipating significant snow melt as temperatures in the mountains 
should be in the 30s throughout the event. However...having said 
that...central and northern sections will need to be monitored for 
possible expansion of the watches if conditions change. 


&& 


Tides... 
still not at the high portion of our tide cycle and winds/waves 
should be only moderately high...so we're not expecting 
significant problems along the coast. Appears the storm surge will 
run about a foot above normal. Having said that...some areas have had 
a tough winter with significant beach erosion...so the most 
vulernable northeast facing beaces in coastal York and coastal 
Rockingham may have some additional minor issues. No additional statements 
or advisories expected at this time. 


&& 


Gyx watches/warnings/advisories... 
ME...Flood Watch from late tonight through Tuesday afternoon for 
mez018-019-023>028. 
New Hampshire...Flood Watch from late tonight through Tuesday afternoon for 
nhz005>010-013-014. 
Marine...Small Craft Advisory from 5 am to 6 PM EDT Tuesday for anz151- 
153. 
Gale Warning from 5 am to 6 PM EDT Tuesday for anz150-152-154. 


&& 


$$ 
Jc 

National Weather Service Glossary of Abbreviations

Non-Expanded Version (with abbreviations)