Area Forecast Discussion
Issued by NWS Caribou, ME

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000 FXUS61 KCAR 281030 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 630 AM EDT Wed Sep 28 2016 .SYNOPSIS... High pressure will build south across the region today into Saturday. Low pressure will gradually approach from the south on Sunday. && .NEAR TERM /THROUGH TONIGHT/... 630 AM update...No significant changes were needed this morning. Still lots of clouds out there, so increased sky cover for a few more hours, until we start to see some breaks a bit later this morning. Also removed the mention of fog from the coast as all obs and webcams are indicating a stratus deck rather than fog. Otherwise, any other adjustments were minor. Previous discussion...Surface high pressure will remain centered just to our northeast today and tonight. Meanwhile, a large upper low will meander across the Great Lakes and Ohio River Valley. Low level moisture will continue to stream into our area on east northeast winds, keeping plenty of clouds around through today and tonight. A stray sprinkle or two can`t be ruled out through this afternoon, but better rain chances - albeit still small - will exist across coastal areas this evening and overnight as a weak low moves by to our south. Afternoon highs will range from the lower and mid 50s in the north to around 60 in interior Downeast locations. Temperatures tonight will bottom out around 40 in the north and in the upper 40s to around 50 Downeast. && .SHORT TERM /THURSDAY THROUGH FRIDAY/... A split flow omega blocking pattern will be in effect by the the short term, with our FA downstream upper ridge psn from a large upper low in the OH vly, near the confluence zone between the nrn and srn branches of the upper jet. What this will entail is that sfc hi pres ovr QB and Nrn Can maritimes will hold ovr the FA during this tm, keeping deeper ovrrng cldnss and any rn just S of our FA. Hi temps Thu will be a little below avg, followed by a cool ngt across the N Thu ngt, which will be least impacted by hi cldnss. Hi temps Fri look to be milder with fcst aftn 925mb temps about 3 deg c warmer than Thu aftn. Low temps Fri ngt will not be quite as cool as Thu ngt with a little more in the way of hi and mid cldnss, even across the N and milder 925mb temps than Thu ngt. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... The blocking ridge both at the sfc and alf will slowly give way to the E durg the weekend as the upper low begins to dislodge from the OH vly and move toward the ENE. The 28/00z dtmnstc GFS is a little faster to show this than the 00z ECMWF, so our fcst grids try to blend the tmg difference of the cld and rn advc NE into our FA. Because of the tmg uncertainties between the longer range models and relatively low fcst QPF attm, we kept rn PoPs in the chc cat for now, slowly movg chc PoPs NE from coastal Downeast areas late Sat aftn to far nrn areas Sun eve. The best chc of rnfl for the region in the form of shwrs may be with whats left of the upper low as it tracks toward and just S of the FA Sun ngt thru Mon. Depending on the advc of thicker cld cvr on Sat, it is likely that hi temps Sat aftn may be inverted, warmer across the N where more sunshine is likely. Otherwise, fcst hi temps Sun and Mon will be at or just below avg with abv normal ovrngt lows due to the presence of deeper cldnss and shwrs. The 00z CanGem model bridges the gap between the faster cooler GFS and slower warmer ECMWF models in exiting the opening upper low E of our FA by Tue and the drier llvl air mass following this system. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... NEAR TERM: MVFR conditions are expected to prevail at all terminals through this morning, though IFR ceilings will be possible at BGR and BHB until 12z or so. Ceilings will lift to VFR thereafter, but will likely drop back to below 3000 ft by 06z Thursday at most spots; ceilings below 1000 ft will be possible at BGR and BHB. SHORT TO LONG TERM: Mainly VFR xpctd all TAF sites thru this ptn of the fcst...possibly transitioning to MVFR clgs and vsbys across Downeast sites with showers by Sun aftn. && .MARINE... NEAR TERM: The Small Craft Advisory is now in effect from 5 am this morning through Thursday morning. Seas are already approaching 5 feet at both buoys in the outer waters, with gusts around 20 kt. Therefore felt it appropriate to start the SCA a few hours earlier than the previous forecast. Have left the inner waters out for now, as most gusts will remain below 25 kt. SHORT TO LONG TERM: SCA winds and seas should cont ovr the outer MZs at least thru Thu aftn and then slowly diminish Thu ngt and Fri. Primary wv pds will be arnd 8 sec for most of these ptns of the fcst. Kept close to WW3 wv guidance for fcst wv hts this update. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...Small Craft Advisory until 5 PM EDT Thursday for ANZ050-051. && $$ Near Term...Hastings Short Term...VJN Long Term...VJN Aviation...Hastings/VJN Marine...Hastings/VJN

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