Area Forecast Discussion
Issued by NWS Caribou, ME

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000 FXUS61 KCAR 221047 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 647 AM EDT Tue Aug 22 2017 .SYNOPSIS... Low pressure will approach from the west later today. The low will track to our north tonight into Wednesday as it brings a cold front across the area. && .NEAR TERM /THROUGH TONIGHT/... 640 am update... Mild and muggy early this morning across most of the forecast area. Latest surface analysis shows a frontal boundary was situated across far northern Maine from just north of Caribou to Clayton lake. Somewhat drier air just to the north of the boundary with dew points at Frenchville and Clayton Lake down into the upper 50s. The boundary will move back north of the state later today as low pressure tracks to our northwest. Latest meso guidance shows showers and thunderstorms holding off until late this afternoon, so made some minor adjustments to pops this morning. Some patchy fog has also developed early this morning but this should should burn off rather quickly in the next hour or so. Otherwise, only minor adjustments to hourly temps/dew points at this time. previous discussion High pressure will continue to slide to the east of the eastern seaboard through tonight, while low pressure tracks to the northwest of the region. Very warm and humid air will continue to drawn across the region today, as a frontal boundary across northern most Maine early this morning moves back to the north as a warm front. Expect partly to mostly sunny skies today, along with unseasonably warm temperatures. Showers and thunderstorms are expected to develop across western areas late this afternoon in advance of an approaching cold front from the west. High temperatures today are once again expected to range from the low to mid 80s across much of the area away from the immediate coast. The cold front will continue to approach the region from the west this evening, with increasing chances for showers and thunderstorms, as forcing increases in advance of the approaching front. Despite the lack of significant surface based cape tonight, the atmosphere will be highly sheared, with 0-6 km shear values expected to be in the 40 to 50 kt range. This will result in the potential for gusty winds in any thunderstorms. Storm Prediction Center continues with a marginal risk of thunderstorms across mainly northern and western portions of the forecast area today. In addition to the gusty wind potential, another concern will be with regard to locally heavy rainfall. Forecast soundings show deep moist profiles with precipitable water values ranging from 1.5 to 2.0 inches, along with dew point temperatures in the mid to upper 60s. Showers and thunderstorms will begin to diminish from west to east late tonight as the cold front continues to move east across the region. Patchy fog can also be expected tonight. Lows tonight will continue unseasonably mild, ranging from the mid to upper 60s. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... Shwrs and any remaining tstms alg with patchy fog should move msly E of the Rgn by Wed aftn behind a cold front with only nominal additional rnfl. Behind the front, sfc dwpts should fall into the 50s with hi temps being lmtd to the 70s across the N. Cooler and dry conditions should then spread across all of the FA Wed ngt as winds decrease ovrngt. Thu and Thu ngt look to be msly fair and cooler, with prtl cldnss and isold shwrs possible across the N half during the aftn and erly eve hrs as upper lvl s/wv energy moves into the FA from Srn QB. Any shwr activity should dissipate by late Thu ngt with the loss of day tm htg/instability. && .LONG TERM /FRIDAY THROUGH MONDAY/... Models in the long range keep upper lvl troffiness ovr the Rgn Fri thru the weekend and even perhaps into erly next week. Of the longer range models, the GFS is the most aggressive with keeping an upper lvl low ovr the the area with more in the way of implied day tm/erly eve shwrs each day. The 22/00z ECMWF and CANGEM models indicate more ewrd movement of the upper low into the Can maritimes by late weekend and erly next week implying drier conditions for the Rgn. Using CPC`s 6 to 10 day outlook which is calling for increased odds of below normal precip for our area as a tie breaker, we kept max PoPs in the slgt chc category each day/erly eve for now until the models better agree on a specific s/wv for higher PoPs. High and low temps will be at to below avg in the long range spcly across the N and Cntrl due to continual llvl cool advcn and day tm prtl cld cvr. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... NEAR TERM: VFR expected at the terminals most of the daylight hours. Showers and thunderstorms are expected to develop from west to east late this afternoon, and then continue to spread east across the remainder of the region tonight. Patchy fog is also expected to develop tonight, with widespread IFR developing. Could see LIFR conditions developing vicinity of Bar Harbor terminal with very moist air coming in off the Gulf of Maine, with low stratus and fog expected to impact the field. SHORT TO LONG TERM: IFR conditions in shwrs and patchy fog erly Wed morn across all of the TAF sites should improve rapidly to VFR behind the cold front by Wed aftn and cont so Wed ngt thru Sat. && .MARINE... NEAR TERM: Winds/seas will gradually increase today, reaching small craft advisory levels tonight. A small craft advisory has been issued from this evening into Wednesday, except for the intra coastal zone. Visibility is expected to decrease to 1 to 3 nm in areas of fog, along with developing showers and thunderstorms tonight. SHORT TO LONG TERM: SCA conditions ovr the outer MZs along with areas of fog across all of our waters Wed morn should improve by Wed aftn, with any remaining patchy fog dissipating by Wed eve behind a cold front. Winds and wvs should then remain below SCA thresholds thru the remainder of the late week and weekend. Went below WW3 wv guidance values spcly Wed morn where we only went with about 75 percent of the guidance attm given the warm season hi bias due to ovr estimation of sfc wind speeds in a srly sfc wind regime. Primary wv pds will increase from arnd 5 sec Wed to arnd 10 sec by late in the week as the wv type becomes longer pd swell. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...Small Craft Advisory from 8 PM this evening to noon EDT Wednesday for ANZ050-051. && $$ Near Term...Duda Short Term...VJN Long Term...VJN Aviation...Duda/VJN Marine...Duda/VJN is the U.S. government's official web portal to all federal, state and local government web resources and services.