Area Forecast Discussion
Issued by NWS Caribou, ME

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000 FXUS61 KCAR 191352 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 952 AM EDT Wed Jul 19 2017 .SYNOPSIS...
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Weak high pressure will prevail across the region into this morning. A weak cold front will cross Maine tonight. A stronger cold front will cross the area Friday and will be followed by Canadian high pressure Saturday.
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&& .NEAR TERM /THROUGH TONIGHT/...
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950 am update... The first order of business was to allow the dense fog advisory for the coast expire as the dense fog is currently dissipating. Synoptic wise, the latest surface analysis shows a weak cold front situated well to our northwest across central Quebec province. The latest MRMS radar mosaic does show some shower activity just along and ahead of the approaching front. The latest meso scale guidance is showing this activity getting into far northwest Maine after 18z. Based on this, have increased the pops (30 percent) later this afternoon across northern areas. Also bumped pops up (30 percent) early this evening mainly south of Caribou to Houlton as whats left of the shower band weakens as it moves toward down east Maine early this evening. For now, will not mention thunder as a warm layer around H7 will likely inhibit the convective potential. However, there is some cooling aloft by late this afternoon and there is around 500 to 1000J of SB cape being indicated in a corridor from around Houlton down through the central highlands by late this afternoon. HRRR does show some cells developing just east of Houlton 23z-00z time frame. Again, will leave out mention for now since we will be losing surface heating by then but may need to take a closer look at this on next update. In summary, made minor adjustments to raise pops slightly across the north through early this evening, lowered previous max temperature forecast by a couple degrees. previous discussion A weak cold front is approaching the region from the northwest and is expected to move across the State Tonight. A few showers are expected over the next 24 hours but conditions for the most part will be dry. Low clouds along with some patchy fog and drizzle are expected over the southeastern portion of the region today and tonight as moisture moves inland from the ocean. Fog is expected to lift over coastal areas later this morning but low clouds will persist in this area. Fog will also persist over the ocean. Will issue dense fog advisory this morning for coastal zones.
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&& .SHORT TERM /THURSDAY THROUGH FRIDAY/... Wk sfc front wl mv thru CWA and offshore by 12z Thur. Flow aloft wl be zonal on Thur with slightly drier airmass in place but vry little chg in temps. Expecting vry little in the way of pcpn on Thu with dry air at mid-lvls and no frcg to speak of. Maxes wl be in the m80s ovr Downeast zones with coastal zones expected to climb into the 80s due to offshore flow, while St. John Vly wl be in the l80s. Next cdfnt on tap to mv thru the area on Friday. Expect showers and tstms wl accompany this bndry thru drg the aftn. Latest guidance appears to be disjointed on timing of front with NAM bringing it thru CWA by 21z Fri while GFS mvs it thru aft midnight. Given uncertainty on frontal bndry hv opted for just sctd showers in the mrng with showers and tstms drg the aftn. Expect temps on Fri wl be a degree or two cooler than Thur with cld cvr and pcpn expected. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... Extndd fcst wl feature flat, zonal flow thru the weekend with little in the way of pcpn expected. Sfc hipres wl be nosing in fm Canada with slightly blo normal temps expected. Models then begin to diverge by early next week as upr low swings thru the Great Lks region at varying speeds, with CMC global most amplified with upr lvl ridge acrs the Four-Corners region on Mon while GFS/EC flatten ridge out west. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... NEAR TERM: AVIATION: Expect MVFR/IFR conditions today and tonight in KBGR and KBHB. In the north expect VFR conditions today but MVFR/IFR conditions are expected tonight. SHORT TERM: IFR expected Thur morning, especially at BHB, with locally dense fog possible thru daybreak. All terminals will be VFR Thu afternoon tho local MVFR Fri morning at northern sites in low clouds. Potential exists for brief MVFR restrictions in thunder Fri aftn. VFR predominates for the weekend at all terminals. && .MARINE... NEAR TERM: Have used the NAM to initialize the wind grids. Will reduce the model wind speed by 15 percent due to relatively cold sea surface temperatures and inversion suppressing boundary level winds. For Waves: Currently the primary wave system is long period southeast swell (1-2 feet/8 seconds). Wind wave is negligible with wind speeds well under 10 knots. Southeasterly swell is expected to persist for the next 24 hours. Have used the Nearshore Wave Prediction System (NWPS) to initialize the wave heights and will lower model wave heights by 1 foot to account for a high bias from boundary conditions. Will use NWPS for the surf zone forecast. SHORT TERM: Winds and seas will remain well below SCA criteria thru the period. Expect areas of fog over the waters Thu/Thu night before a stronger cold front moves thru on Fri night. && .CAR WATCHES/WARNINGS/ADVISORIES...
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ME...None. MARINE...None.
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&& $$ Near Term...Duda/Mignone Short Term...Farrar Long Term...Farrar Aviation...Duda/Mignone/Farrar Marine...Duda/Mignone/Farrar

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