Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 301354 AFDGYX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME 954 AM EDT THU JUL 30 2015 .SYNOPSIS... A COLD FRONT WILL MOVE INTO THE REGION LATER TODAY... WITH WIDESPREAD SHOWERS AND THUNDERSTORMS EXPECTED ACROSS THE REGION THIS AFTERNOON. SOME OF THESE STORMS MAY BE STRONG TO SEVERE. BEHIND THIS FRONT...DRIER AIR WILL FILTER INTO THE REGION WITH PARTLY TO MOSTLY SUNNY SKIES EXPECTED FRIDAY. ANOTHER DISTURBANCE WILL MOVE INTO NEW ENGLAND ON SATURDAY...INCREASING THE CHANCE FOR SHOWERS AND THUNDERSTORMS ONCE AGAIN. && .NEAR TERM /UNTIL 8 PM THIS EVENING/... 950 AM...WE`RE WARMING QUICKLY IN SOUTHERLY FLOW AHEAD OF THE COLD FRONT SITUATED ALONG THE INTERSTATE 81 CORRIDOR AT 13Z. MODIFIED KALB AND KGYX 12Z RAOBS SUGGEST CAPES NEAR 1000 J/KG AND MODEST SHEAR FOR THIS AFTERNOON AND EARLY EVENING. GREATEST POTENTIAL WILL BE FOR DAMAGING WIND GUSTS WITH THE STRONGER CELLS...WHILE FREEZING LEVELS SUGGEST MINIMAL CHANCE FOR LARGE HAIL. FOR THIS ESTF UPDATE...I MADE MINOR ADJUSTMENTS TO 1ST PERIOD GRIDS TO REFLECT THE 13Z MESONET. CURRENT TIMING SUGGESTS THE LINE OF CONVECTION OVER UPSTATE NEW YORK WILL REACH THE CONNECTICUT VALLEY BETWEEN 1 AND 2 PM...ALTHOUGH SCATTERED CONVECTION COULD DEVELOP EARLIER IN ADVANCE OF THE LINE. PREV DISC... .UPDATE... NO MAJOR CHANGES FOR THIS UPDATE. INPUT OVERNIGHT TEMPERATURES TO UPDATE LAST NIGHT`S OVERNIGHT LOWS. FEW SHOWERS JUST OVER THE CANADIAN BORDER ARE DISSIPATING. && .SHORT TERM /8 PM THIS EVENING THROUGH 6 PM FRIDAY/... THE MAIN AREA/LINE OF SHOWERS AND EMBEDDED THUNDERSTORMS WILL MOVE INTO EASTERN MAINE BY TONIGHT. OVERNIGHT LOWS COOL SOMEWHAT INTO THE UPPER 50S IN THE MOUNTAINS AND THE MID/UPPER 60S SOUTH AS SKIES CLEAR FROM WEST TO EAST. FRIDAY LOOKS SUNNY WITH WEST WINDS BRINGING TEMPERATURES INTO THE UPPER 70S NORTH TO UPPER 80S SOUTH. A DISTURBANCE IN THE UPPER LEVELS MAY BRING A FEW CLOUDS OR A SPRINKLE TO FAR NORTHERN EAST MAINE. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... HIGH IMPACT WEATHER POTENTIAL: ISOLATED THUNDERSTORMS POSSIBLE EACH AFTERNOON THROUGH EARLY NEXT WEEK. A FEW SEVERE STORMS ARE POSSIBLE...BUT WIDESPREAD SEVERE WEATHER UNLIKELY. PATTERN SUMMARY: NAEFS/EUROPEAN ENSEMBLE IN GOOD AGREEMENT ON THE DEVELOPMENT OF LONGWAVE TROUGHING CENTERED NEAR HUDSON BAY...AS CURRENT POTENT MOBILE SHORTWAVE TROUGH OVER NORTHERN ONTARIO GROWS IN SCALE AS IT STALLS IN THIS REGION. THIS TROUGH WILL BE THE PRIMARY GOVERNING FEATURE FOR OUR WEATHER THROUGH THE LONG TERM FORECAST PERIOD...WITH NUMEROUS SHORTWAVE DISTURBANCES ROTATING AROUND IT...AND PROVIDING ONGOING CHANCES FOR SHOWER/STORM ACTIVITY. THIS EASTERN NOAM TROUGHING WON/T BE ANYTHING SPECTACULAR FROM AN ANOMALY STANDPOINT...WITH TEMPERATURES IN THE LLEVELS VERY CLOSE TO SEASONAL NORMS. ACCESS TO MOISTURE WILL BE SOMEWHAT LIMITED...WITH TRAJECTORIES FAVORING A SOURCE REGION OF AIR THAT REACHES NEW ENGLAND ORIGINATING OVER THE UPPER MIDWEST. NO SIGNIFICANT STORM SYSTEMS FORESEEN DURING THIS PERIOD...WITH PRECIPITATION AMOUNTS HIGHLY LOCALIZED /DUE TO THE CONVECTIVE NATURE OF ANYTHING THAT FALLS/. WITH THE PRIMARY JET AXIS NEARBY AND SIGNIFICANT WESTERLY FLOW AT MID LEVELS...WILL HAVE TO KEEP AN EYE OUT FOR THE POTENTIAL OF ISOLATED SEVERE STORMS WITH EACH BOUT OF CONVECTION THROUGH THE PERIOD...ALTHOUGH INSTABILITY LOOKS TO BE A LIMITING FACTOR. DETAILS: SHORTWAVE IN THE WESTERLY FLOW ALOFT PINWHEELS THROUGH THE REGION LATE SATURDAY-SATURDAY NIGHT. MOISTURE WILL BE MORE LIMITED THAN WITH TODAY/S FRONT...LIMITING INSTABILITY DESPITE ROBUST FLOW AT MID LEVELS. THUS...WHILE SCATTERED SHOWER AND EMBEDDED STORM DEVELOPMENT APPEAR LIKELY...WITH ACTIVITY INITIATING IN THE MOUNTAINS AND THEN PROGRESSING SOUTH AND EAST. SEVERE THREAT WILL BE LOW GIVEN THE LACK OF SIGNIFICANT INSTABILITY...BUT WILL HAVE TO KEEP AN EYE ON THIS AS WINDS ALOFT WOULD SUPPORT A MORE SIGNIFICANT THREAT GIVEN IMPRESSIVE WINDS ALOFT. BEHIND THIS FEATURE...LESS CONVECTIVE COVERAGE APPEARS LIKELY AS THE COLUMN DRIES ON SUNDAY...WITH ISOLATED SHRA ACTIVITY POSSIBLE DURING THE AFTERNOON IN THE MOUNTAINS ...WITH DRY CONDITIONS LIKELY ELSEWHERE. FORCING/MOISTURE INCREASES AGAIN AS WE REACH NEXT WEEK WITH REASONABLE AGREEMENT THAT THE LONGWAVE TROUGH AXIS CENTERED OVER HUDSON BAY WILL SHIFT SOMEWHAT EAST WITH CONFLICTING SIGNALS ON THE SHARPNESS/TIMING OF ADDITIONAL SHORTWAVE ENERGY ROTATING AROUND THIS FEATURE. WITH THE PROXIMITY OF MID LEVEL FORCING...WILL CONTINUE AFTERNOON SHOWER/STORM CHANCES WITH OVERNIGHTS LIKELY REMAINING DRY. BY WEDNESDAY /AND BEYOND/...IF THIS EASTWARD SHIFT COMES TO FRUITION...A DRIER AND SOMEWHAT COOLER PATTERN MAY ARRIVE TO END THE PERIOD WEDNESDAY. TEMPERATURES: WITH TEMPERATURES ALOFT VERY CLOSE TO WHERE THEY SHOULD BE THIS TIME OF YEAR...EXPECT A PERIOD OF SEASONAL TEMPERATURES THROUGH THIS PERIOD. && .AVIATION /14Z THURSDAY THROUGH MONDAY/... SHORT TERM...AREAS OF PATCHY LIFR FOG ALONG THE COAST AND KAUG WILL IMPROVE AROUND DAYBREAK. SHOWERS AND EMBEDDED THUNDERSTORMS WILL KEEP TERMINALS IN MVFR CONDITIONS OR LOWER AT TIMES TODAY INTO THIS EVENING. MORE DENSE FOG EXPECTED TONIGHT. LONG TERM...WIDESPREAD MVFR/IFR NOT FORESEEN THROUGH THE LONG TERM PERIOD. RATHER...OCCASIONAL BOUTS OF ISOLATED MVFR/IFR IN SHRA/TSRA EACH AFTERNOON APPEAR LIKELY...ESPECIALLY HIE/LEB. PATCHY OVERNIGHT FOG POSSIBLE EACH MORNING GIVEN THIS TYPE OF PATTERN...PARTICULARLY IN AREAS WHERE AFTERNOON RAIN OCCURS. && .MARINE... SHORT TERM...THE OUTER WATERS APPROACH 20 KTS AND 5 FT FOR A FEW HOURS LATE TONIGHT BEHIND A COLD FRONTAL PASSAGE. OPTED NOT TO ISSUE A SCA FOR THIS. LONG TERM...SOUTHWESTERLY WINDS WILL GENERALLY REMAIN BELOW SMALL CRAFT LEVELS THROUGH THE WEEKEND WITH STRONGER WINDS POSSIBLE EARLY NEXT WEEK AS LOW PRESSURE WORKS THROUGH THE REGION MONDAY- TUESDAY. WAVES WILL NEAR SMALL CRAFT LEVELS SATURDAY NIGHT...AND AGAIN EARLY NEXT WEEK COINCIDENT WITH THESE STRONGER WINDS. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...NONE. && $$ ES

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