Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 190920 AFDGYX Area Forecast Discussion National Weather Service Gray ME 420 AM EST Sun Nov 19 2017 .SYNOPSIS...
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Low pressure moving into Canada will drive a cold front through the area this morning. Temperatures will continue to creep up ahead of the front...with areas of rain through mid morning. The front will come through with increasing winds...which may gust in excess of 40 mph at times through the evening. Temperatures will continue to fall behind the front and gusty winds will linger right through Monday. We will get a brief warm up on Tuesday but another cold front moves through on Wednesday with cold air spilling in for the latter half of the week.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Low pressure located over the eastern end of Lake Ontario early this morning will move up the St. Lawrence valley bringing a cold front through the region this afternoon. The warm front has pushed northwards through the region with temperatures rising slightly overnight. This has put the entire region above freezing changing the freezing drizzle and sleet from earlier tonight over to rain and so the Winter Weather Advisory will be cancelled with this update. Warm air has moved in even further aloft with temperatures in the mid 40s at 4000ft. These warm temperatures will mix down to the surface as the cold front approaches this morning. The southern portion of the CWA may reach 50F. The cold front will cross the region this afternoon. This front is accompanied by a 50-60kt LLJ which will bring scattered wind gusts of 40-45mph to the surface. These winds will be most favored in the coastal plain where downsloping will enhance the winds and a wind advisory remains in place for these area.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
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Overnight the tight pressure gradient behind the front will keep winds in the 15-20mph range overnight. Normally this in combination with the cloud cover would lead to slightly warmer overnight low temperatures but with the continued cold advection as temperatures drop to around -13C at 850mb expect the lows to drop to the teens with wind chill in the single digits in the north. Monday will see clearing for all but the international border as upslope snow showers persist through the start of the morning. Winds will continue to gust in the 25mph range throughout the day.
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&& .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
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Tue will bring ridging surface and aloft...allowing winds to decrease and temps to cool off Mon night. Return flow quickly develops Tue...which should be a mild day relative to recent high temps. Model guidance in the extended continues the growing consensus towards a passing trof Wed with low pressure well out to sea. The main Nrn stream s/wv trof shears out thru Quebec...and so the frontal passage will be rather weak across the Northeast. An increase in upslope snow showers is likely...but widespread precipitation is unlikely given the forcing. One aspect to the keep an eye on however will be trailing energy in the base of the trof. As it lags it may allow some moisture from the ocean low to be entrained into the region. This could bring more precipitation into coastal zones. The multi-model consensus high chance PoP seems reasonable at this range. Zonal flow aloft continues Thu into Fri...with a quick moving s/wv likely to enhance upslope snow showers in that time frame. Heading into the weekend there remains a strong signal for a deep Ern CONUS trof and low pressure in the vicinity. There remains a good deal of uncertainty regarding evolution...but certainly looks like the best chance in the next 7 days of widespread precip across the region.
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&& .AVIATION /09Z SUNDAY THROUGH THURSDAY/...
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Short Term...Widespread rain and fog has ceilings at IFR to LIFR across the region and will remain so through daybreak. In the morning, increasing southwesterly winds ahead of the cold front will help to mix especially teh coastal plain and cloud decks should increase. Rain may briefly end as temperatures climb in the warm sector. A cold front will cross the region this afternoon with brief period of more intense precipitation and wind gusts to 35kts from the west. The precipitation will end and winds will diminish as conditions return to a blustery VFR overnight and into Monday for all but the northern Mountains where MVFR upslope snow showers remain. Long Term...Generally VFR conditions expected this week. In a pattern dominated by Wly flow...upslope clouds and SHSN will be possible at HIE...but otherwise terminals will only see a threat of flight restrictions on Wed. A passing cold front may bring scattered SHRA/SN...mainly across the interior...while a low pressure passes well out to sea. The best chance for local IFR conditions will be inland where temps will stay cold enough for SN.
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&& .MARINE...
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Short Term... A cold front will cross the waters this afternoon. Ahead of the front a few gust to 35kts are possible in southwesterly flow. Winds will abruptly increase with frontal passage becoming west with gusts to 45kts on the outer waters and 30kts on the bays. Not out of the question to see one of the higher elevation observation platforms gust to storm force but expect mostly widespread gale conditions so have left the gale warning as is. Long Term...Gale force wind gusts will diminish outside the bays Mon night. There may be a brief window of sub- SCA gusts before strengthening SWly flow approaches 25 kts. Winds and seas diminish Wed.
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&& .GYX WATCHES/WARNINGS/ADVISORIES...
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ME...Wind Advisory from noon today to midnight EST tonight for MEZ012-018>028. NH...Wind Advisory from noon today to midnight EST tonight for NHZ004-006-008>010-012>015. MARINE...Gale Warning until midnight EST tonight for ANZ150>154.
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&& $$ NEAR TERM...Curtis SHORT TERM...Curtis LONG TERM...Legro AVIATION...Curtis/Legro MARINE...Curtis/Legro

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