Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 201122 AAB AFDGYX Area Forecast Discussion...UPDATED National Weather Service Gray ME 722 AM EDT Tue Jun 20 2017 .SYNOPSIS... Relief from the muggy air mass is on the way today. The cold front will finally cross the area from west to east...allowing much more comfortable humidity levels. We will still have to watch out for some scattered showers or a thunderstorm this afternoon behind the front. After dark the showers will dissipate and temperatures will fall to more pleasant readings for this time of year. The final trough pushes through the area Wednesday with more scattered showers...though these will be more focused in the higher terrain. The next more significant system approaches late Thursday into Friday bringing a return to unsettled weather. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Update...Trailing edge of the better forcing is now working into SW NH at this hour. Showers will be most likely the next couple of hours across Wrn ME and in the mtns. After this batch moves thru the focus will then turn towards the mtns...where the upper trof will generate afternoon showers/storms. Previous discussion...It is much quieter this hour across the forecast area...though we do have another weak s/wv trof moving up thru the Mid Atlantic. This will help to force an area of showers that will move over parts of the forecast area. At this time hi- res model forecasts and latest radar trends suggest the most likely spot for showers will be along and S of the foothills. I increase to likely PoP in the next couple of hours and keep it there until closer to mid morning when subsidence behind that wave sweeps thru. SW flow is also forecast to increase after daybreak. This will help to mix out the low levels and really significantly dry out the air. The Midcoast may take a little longer than the rest of the area...but eventually dew points will be at or approaching the 50s by evening. Until then...with some sunshine we should see the 80s for most of the area today. Even with the boundary layer drying out...the warm temps should be enough for some low topped instability showers this afternoon. With the upper trof still hanging back...cyclonic flow and lower heights aloft will support scattered convection. The forecast soundings do show some CAPE...albeit meager...so I cannot rule out a rumble of thunder with any shower...but I do not expect it to be widespread. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... Tonight into Wed the last in a series of s/wv trofs will pivot around the upper trof over the Great Lakes. This will bring another round of enhanced shower activity...especially in the mtns. By no means will this be a washout though...and temps and humidity will be comfortable. PoP is mainly chance in the N and slight chance S of there. Model guidance has also started lifting the upper low out quicker...sending the best forcing for ascent to our N as well. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... The deterministic models are now in decent agreement on the longwave pattern through the upcoming weekend and into early next week. We begin the period with weak ridging arriving for Wednesday night and Thursday. A warm front pushes into New England Thursday night ahead of the next impulse racing eastward along the U.S. - Canadian border. The warm front slides northward across the forecast area on Friday as low pressure races east across Quebec province...with the trailing cold front to cross the region late Friday and Friday night. We`re left with residual troffiness to start the weekend with the prospect for some clouds and scattered convection mainly across the higher terrain and along the international border. We`ll see a brief break in the active pattern on Sunday under weak ridging before the next shortwave impulse drives a cold front across the area on Monday to begin the new work week. && .AVIATION /11Z TUESDAY THROUGH SATURDAY/... Short Term...Widespread MVFR this morning...with areas of IFR/LIFR lingering in coastal stratus. Conditions should more or less hold steady thru morning...and then start to mix out as SW flow increases and drier air works in the from the W. Another wave along the front may bring more SHRA early this morning...mainly along the coast. Then Nrn half of the forecast area will likely see afternoon SHRA/TSRA...with LEB and HIE being most likely to see precip. Otherwise VFR developing outside of HIE...where some upslope MVFR CIGs are possible. Long Term... Fri - Fri night...Areas of MVFR in SHRA/TSRA with lcl IFR in fog and drizzle. Sat...Sct MVFR in mtn -shra. && .MARINE... Short Term...SCA conditions will slowly diminish today. SW winds may occasionally gust to 25 kts outside the bays...with seas 5 to 7 ft diminishing more slowly. SCA may need to be extended for seas into the evening. Long Term... Thu night - Fri...Small Craft Conditions are possible outside the bays. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory until 6 PM EDT this evening for ANZ150- 152-154. && $$ NEAR TERM...Legro SHORT TERM...Legro LONG TERM...Schwibs AVIATION...Legro/Schwibs MARINE...Legro/Schwibs

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