Area Forecast Discussion
Issued by NWS Portland, ME

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745 FXUS61 KGYX 261032 AFDGYX Area Forecast Discussion National Weather Service Gray ME 632 AM EDT THU MAY 26 2016 .SYNOPSIS... A ridge of high pressure will crest across the area this morning before sliding offshore this afternoon. Summer like temperatures will be tempered a bit near the coast as light winds turn onshore by afternoon. A warm front will stall over the region tonight and Friday before finally pushing east of the region on Saturday. A cold front will cross the region Saturday night then stall just to our south on Sunday. The front will return north as a warm front on Memorial Day. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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628 AM...minor ESTF update to reflect the current mesonet in near term grids. PREV DISC... At 06z...a 1009 millibar low was over Eastern New Brunswick province with a trailing cold front through the gulf of Maine. A ridge of high pressure extended southward into Western New England. Goes infrared imagery showed clear skies across the forecast area under the building ridge. The light winds and clear skies were allowing patchy valley stratus and fog to form across the area. For today...early morning stratus and fog should burn off quickly with sunshine under the cresting ridge pushing temperatures into the 80s in many locations...but turning cooler by afternoon ear the coast as the light synoptic flow turns onshore. Clouds will increase over southern and Western sections late today ahead of approaching warm front with a late day rain shower possible over southwest New Hampshire.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... For tonight...warm air advection clouds will spread north and east across the remainder of the area. Onshore flow should also introduce some late night drizzle and fog to the coastal plain. otherwise...expect a few showers and thunderstorms to precede the warm front overnight. Lows tonight should be mainly in the 50s. Friday will be a tale of two regimes with summer time heat developing across much of New Hampshire into the Maine mountains and International border area while further east clouds should hang tough with an onshore breeze as the surface warm front makes little if any progress against the cool...damp...stable marine layer. Expect we`ll see drizzle and fog linger into the afternoon at the coast...especially north and east of Casco Bay. We`ll see scattered convection continue across the forecast area as well with the best chance for thunder from the Connecticut valley northward along the International border area. Highs will range from the 80s across the Connecticut valley and International border to the upper 50s in mid coast Maine. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... Overall pattern in the extended remains consistent with seasonably strong ridging building in from the Wrn Atlantic. With mean ridge axis more or less overhead...the forecast area will be in the battle ground between summer-like warmth and spring-like chill. One common theme is dry wx...with ECMWF EPS producing less than 0.75 inches QPF across the forecast area thru day 10. While any individual shower or storm could drop more than that...it does point towards an an overall lack of robust forcing. More specifically...model guidance shows mid level temps warming into Sat. GEFS forecasts of greater than 2 SD anomalies would suggest deterministic guidance may be biased a bit too cool. Outside of the sea breeze...winds will be favorable for interior warmth...and so I went above guidance by a couple of degrees...especially the Srn NH traditional warm spots. One note about Sat regarding precip chances. While scattered showers and storms are possible just due to the hot and increasingly humid air mass...some organized convective wx is not out of the question. The region will reside on the Srn edge of strong Wly flow aloft. We lack a strong trigger to focus convection...but some solutions...like the 26.00z GFS show a sub 400 mb PV anomaly crossing the Maritimes Sat afternoon. If that forcing could extend a little farther SW...a stronger storm or two is possible. By Sun that PV anomaly will help leave behind a boundary which the pres gradient will likely push Wwd. The Ern half of the forecast area looks to be much cooler Sun...though farther W parts of the CT River Valley might remain very warm. Beyond the weekend we look to remain with warmer than normal temps. Precip chances are much less confident...with weak forcing and possible moisture influences due to Invest 91 in the Wrn Atlantic forecast to move towards the Carolinas this weekend and early next week. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... Short Term /through Friday/...sct mvfr and lcl ifr through 12z in valley stratus and fog...otw vfr throughout. Areas of mvfr dvlpg tonight in -shra/-tsta with lcl ifr vcnty of the coast in drizzle and fog. Areas of mvfr continue Fri in sct -shra/tsra with lcl ifr lingering vcnty of the coast in drizzle and fog. Long Term...Ridging looks to dominate the pattern for the extended...which will favor drier conditions and more VFR than not. With warmer air masses and moisture increasing in the area...the risk for afternoon SHRA and TSRA will remain. MVFR or lower will be possible in any heavier precip. In addition...front moving swwd thru the area Sun may bring some marine low clouds to coastal terminals. && .MARINE... Short Term /through Friday/...Quiet on the waters with winds and seas remaining below Small Craft threshold. Long Term...Winds and seas look to remain below SCA thresholds with ridging in control of the region. Post front on Mon there is possibility of seas nearing 5 ft outside of the bays...but confidence is low at this time. && .FIRE WEATHER... Today will be one of the only dry days this week. Afternoon relative humidity values may hover near 30 percent...but winds will be light. Moderate to high humidity levels return for tonight through the start of the holiday weekend. We are forecasting all areas to receive rainfall for the end of the week into the upcoming weekend...although amounts should be relatively light. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ es

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