Area Forecast Discussion
Issued by NWS Buffalo, NY

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000 FXUS61 KBUF 191751 AFDBUF AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BUFFALO NY 151 PM EDT FRI SEP 19 2014 .SYNOPSIS... HIGH PRESSURE CENTERED OVER THE SAINT LAWRENCE VALLEY WILL DRIFT EASTWARD ACROSS NEW ENGLAND THIS AFTERNOON BEFORE MOVING OFF THE COAST TONIGHT AND SATURDAY. THIS WILL NOT ONLY PROVIDE US WITH FAIR WEATHER THROUGH THE FIRST HALF OF THE WEEKEND...BUT THE CLOCKWISE CIRCULATION AROUND THE HIGH WILL PUMP NOTABLY WARMER AIR ACROSS OUR REGION FOR SATURDAY. TEMPERATURES ACROSS THE WESTERN COUNTIES WILL BE MORE TYPICAL OF THE SECOND HALF OF AUGUST. A FRONTAL SYSTEM WILL THEN LIKELY GENERATE SOME SHOWERS FOR THE SECOND HALF OF THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... HIGH PRESSURE CENTERED OVER THE ST LAWRENCE VALLEY THIS MORNING WILL DRIFT EASTWARD ACROSS NEW ENGLAND DURING THE MIDDAY AND AFTERNOON. THIS WILL PROVIDE FULL SUNSHINE ACROSS THE REGION THIS AFTERNOON... WITH H85 TEMPS IN THE SINGLE DIGITS SUPPORTING AFTERNOON TEMPERATURES IN THE MID 60S ACROSS LOWER ELEVATIONS. TONIGHT...THE SFC HIGH WILL MOVE OFF THE NEW ENGLAND COAST WHILE A SHORTWAVE DIGGING ACROSS THE CANADIAN PRAIRIES WILL PUSH A DEVELOPING FRONTAL SYSTEM ACROSS THE UPPER MISSISSIPPI VALLEY. WHILE FAIR DRY WEATHER WILL REMAIN IN PLACE ACROSS OUR FORECAST AREA... THE AFOREMENTIONED SYNOPTIC PATTERN WILL ESTABLISH A DEEPENING SOUTHERLY FLOW OVER THE LOWER GREAT LAKES. THE WARMER FLOW WILL BE HIGHLIGHTED BY A 40KT LOW LEVEL JET THAT WILL HELP TO HOLD OUR TEMPERATURES IN THE 50S (UP 40S LEWIS CO) DURING THE OVERNIGHT HOURS. THESE OVERNIGHT READINGS WILL AVERAGE SOME 15 DEG F HIGHER THAN THOSE FROM EARLY THIS MORNING. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... ON SATURDAY...SPRAWLING SURFACE HIGH PRESSURE OFF THE NEW ENGLAND COAST WILL CONTINUE TO SLOWLY DRIFT EASTWARD THROUGH THE DAY...WHILE A COMPLEX LOW PRESSURE SYSTEM WILL SLIDE FROM CENTRAL ONTARIO AND THE UPPER GREAT LAKES TO THE ONTARIO/QUEBEC BORDER. AT THIS POINT... IT STILL APPEARS THAT THE UPSTREAM LOW WILL REMAIN FAR ENOUGH TO OUR NORTH AND WEST TO ALLOW FOR ANOTHER DRY DAY...SAVE FOR A SLIGHT CHANCE OF A STRAY SHOWER OR TWO ACROSS THE SAINT LAWRENCE VALLEY. IN TERMS OF CLOUD COVER...A SLUG OF LOW LEVEL MOISTURE CIRCULATING NORTHEASTWARD AROUND THE BACK SIDE OF THE DEPARTING RIDGE WILL BRING SOME CLOUDS TO PORTIONS OF THE FINGER LAKES AND NORTH COUNTRY DURING THE MORNING...OTHERWISE A PARTLY TO MOSTLY SUNNY DAY CAN BE EXPECTED WITH OUR REGION SITUATED WITHIN THE DEEPENING WARM SECTOR OF THE SLOWLY ENCROACHING LOW. WITH RESPECT TO TEMPERATURES...THE STRENGTHENING WARM AIR ADVECTION PATTERN ACROSS OUR REGION WILL HELP TO PUMP 850 MB READINGS UP TO THE +10C TO +13C RANGE BY EARLY SATURDAY AFTERNOON. COUPLED WITH THE AFOREMENTIONED SUNSHINE AND A TIGHTENING PRESSURE GRADIENT THAT WILL PROMOTE INCREASINGLY BREEZY CONDITIONS AND RESULTANT GOOD MIXING... THIS WILL ALLOW SURFACE TEMPERATURES TO REBOUND TO SUMMERTIME LEVELS. EXPECT HIGHS TO CLIMB INTO THE MID TO UPPER 70S IN MANY AREAS...EXCEPT ACROSS INTERIOR PORTIONS OF THE NORTH COUNTRY WHERE READINGS WILL PEAK IN THE UPPER 60S TO LOWER 70S. THE WARMEST READINGS OF ALL WILL BE FOUND ACROSS THE LAKE PLAINS OF FAR WESTERN NEW YORK...WHERE THE AIRMASS WILL BE WARMEST...SKIES WILL BE SUNNIEST...AND GOOD DOWNSLOPING FROM A STRONG SOUTH-SOUTHWESTERLY BREEZE WILL GIVE TEMPS AN ADDED BOOST. IF THINGS WORK OUT RIGHT... WOULD NOT BE SURPRISED TO SEE A FEW LOCATIONS IN THIS LATTER REGION BREACH THE 80 DEGREE MARK. AS MENTIONED ABOVE...IT WILL BE BREEZY AS WELL WITH WIND GUSTS AS HIGH AS THE 30-35 MPH RANGE LIKELY ACROSS FAR WESTERN NEW YORK. SATURDAY NIGHT AND SUNDAY...DEEPENING LARGE-SCALE TROUGHING WILL DIG ACROSS THE GREAT LAKES REGION...WHILE ITS ATTENDANT COMPLEX SURFACE REFLECTION SLIDES EASTWARD ACROSS QUEBEC PROVINCE. IN THE PROCESS... THIS LATTER FEATURE WILL PUSH ITS TRAILING COLD FRONT ACROSS WESTERN AND NORTH CENTRAL NEW YORK DURING SUNDAY. LARGE-SCALE FORCING AND MOISTURE ALONG/AHEAD OF THE FRONT STILL APPEAR PLENTY SUFFICIENT TO SUPPORT A LIKELIHOOD OF SHOWERS LATER SATURDAY NIGHT AND SUNDAY... WHEN A FEW THUNDERSTORMS MAY ALSO BE POSSIBLE GIVEN THE PRESENCE OF SOME LIMITED INSTABILITY. AT THIS POINT...WILL CONTINUE TO COVER THE APPROACH AND PASSAGE OF THE FRONT WITH A SWATH OF HIGH LIKELY POPS LATER SATURDAY NIGHT AND SUNDAY...WITH DRY SLOTTING BEHIND THE FRONT THEN LEADING TO A NOTICEABLE WEST-EAST REDUCTION IN SHOWER CHANCES SUNDAY AFTERNOON. TEMPERATURE-WISE...VERY MILD CONDITIONS WILL PERSIST SATURDAY NIGHT WITH OUR REGION REMAINING FIRMLY WITHIN THE WARM SECTOR AND CONSEQUENTLY UNDER THE INFLUENCE OF A DEEP SOUTHWESTERLY FLOW...WHICH SHOULD RESULT IN READINGS DROPPING NO LOWER THAN THE LOWER TO MID 60S. INCREASED CLOUD COVER/PRECIPITATION COVERAGE ALONG WITH THE COLD FRONTAL PASSAGE WILL THEN HELP TO HOLD READINGS DOWN CLOSER TO SEASONAL AVERAGES ON SUNDAY...WHEN HIGHS WILL GENERALLY RANGE FROM THE UPPER 60S TO LOWER 70S. SUNDAY NIGHT...THE MAIN UPPER LEVEL TROUGH AXIS WILL PASS ACROSS THE REGION...ALONG WITH AN ASSOCIATED SECONDARY SWATH OF WRAPAROUND MOISTURE. THIS WILL SUPPORT MOSTLY CLOUDY SKIES AND ANOTHER ROUND OF MUCH MORE SCATTERED SHOWERS...WHILE STEADY COOL AIR ADVECTION FORCES TEMPERATURES TO FALL BACK TO THE UPPER 40S TO LOWER 50S TO CLOSE OUT THE SHORT TERM PERIOD. && .LONG TERM /MONDAY THROUGH THURSDAY/... MONDAY AND TUESDAY...UPPER LEVEL TROUGHING WILL LINGER ACROSS EASTERN CANADA AND THE NORTHEASTERN CONUS...WITH THE RESULTANT COOL CYCLONIC FLOW LEADING TO ANOTHER ROUND OF BELOW NORMAL TEMPERATURES. THE COOLEST WEATHER WILL BE ON MONDAY...WHEN 850 MB TEMPS WITHIN A FEW DEGREES OF ZERO CELSIUS WILL ONLY BE SUPPORTIVE OF HIGHS IN THE MID TO UPPER 50S IN MOST LOCATIONS. WHILE THIS AIRMASS WILL BE ON THE COOL SIDE...IT WILL ALSO BE RATHER DRY...WITH THE BULK OF ANY MOISTURE LARGELY CONFINED TO THE LOWEST 5 KFT OR SO OF THE TROPOSPHERE. THIS WILL SERVE TO GREATLY LIMIT SHOWER CHANCES...WITH THE BULK OF THESE MAINLY DRIVEN BY THE PASSAGE OF A TRAILING SHORTWAVE ON MONDAY AND A SECONDARY SURFACE TROUGH LATER MONDAY NIGHT/TUESDAY...WITH THE LATTER PRIMARILY AFFECTING NORTHERN NEW YORK. WITH THE ABOVE IN MIND...WILL JUST KEEP SOME LOW CHANCE POPS IN PLAY AS APPROPRIATE...WITH ANY LAKE RESPONSE EXPECTED TO BE SEVERELY LIMITED BY BOTH THE DRY NATURE OF THE AIRMASS AND RELATIVELY LOW INVERSION HEIGHTS. AFTER THAT...CONDITIONS SHOULD IMPROVE MARKEDLY FOR WEDNESDAY AND THURSDAY AS STRONG RIDGING BUILDS ACROSS THE REGION AT ALL LEVELS. PLENTY OF ASSOCIATED DRY AIR AND SUBSIDENCE/WARMING ALOFT SHOULD RESULT IN DRY WEATHER AND A NICE RECOVERY IN TEMPERATURES...WITH DAYTIME HIGHS WARMING TO AROUND 70 DEGREES OR SO BY THE END OF THE PERIOD. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... VFR WILL PREVAIL THROUGH THIS EVENING WITH CLEAR SKIES AS HIGH PRESSURE DRIFTS SLOWLY OFF THE NEW ENGLAND COAST. LATER TONIGHT INTO SATURDAY MORNING A PLUME OF LOW LEVEL MOISTURE OVER THE MID ATLANTIC STATES WILL BE DRAWN NORTHWARD ON INCREASING SOUTHERLY FLOW. THIS MAY PRODUCE SOME LOW STRATUS ACROSS THE HIGHER TERRAIN OF THE SOUTHERN TIER AND FINGER LAKES...AND ALSO EAST OF LAKE ONTARIO WITH AREAS OF MVFR/IFR CIGS. SOME OF THIS MAY IMPACT KJHW AS WELL. INCREASING SSW DOWNSLOPE FLOW WILL PREVENT THE LOWER CLOUDS FROM MAKING IT TO THE LOWER ELEVATIONS...WITH VFR PREVAILING AT THE REST OF THE TAF SITES. A LOW LEVEL JET WILL CROSS THE REGION TONIGHT INTO EARLY SATURDAY. IT APPEARS THE BOUNDARY LAYER WILL REMAIN MIXED ENOUGH TO PREVENT ANY TRUE LOW LEVEL WIND SHEAR...ALTHOUGH MECHANICAL TURBULENCE WILL INCREASE IN THE LOWEST LEVELS. ON SATURDAY THE LOW STRATUS ACROSS THE HIGHER TERRAIN SHOULD MIX OUT BY MIDDAY...AND LEAVE VFR ACROSS THE ENTIRE REGION FOR THE AFTERNOON WITH A MIX OF SOME CUMULUS AROUND 5K FEET AND INCREASING MID/HIGH CLOUDS. IT WILL BECOME QUITE BREEZY WITH SSW WINDS GUSTING TO 20-25 KNOTS ACROSS MUCH OF THE REGION...AND 25-30 KNOTS NORTHEAST OF LAKE ERIE FROM KBUF-KIAG. OUTLOOK... SUNDAY...AREAS OF MVFR AND SPOTTY IFR WITH OCCASIONAL SHOWERS AND A CHANCE OF A THUNDERSTORM. MONDAY AND TUESDAY...MAINLY VFR WITH A SLIGHT CHANCE OF A SHOWER. WEDNESDAY...VFR EXCEPT FOR LOCAL IFR IN SOUTHERN TIER VALLEY FOG IN THE MORNING. && .MARINE... HIGH PRESSURE WILL DRIFT EAST FROM THE ST LAWRENCE VALLEY TODAY. THIS WILL PRODUCE AN EASTERLY FLOW ACROSS THE LOWER GREAT LAKES WITH NEGLIGIBLE WAVES. THE EXCEPTION WILL BE OVER OFFSHORE AND CANADIAN WATERS OF LK ONTARIO WHERE SOMEWHAT STRONGER EASTERLY WINDS WILL PRODUCE WAVES IN THE 3-5 FOOT RANGE THROUGH EARLY AFTERNOON...MAINLY FROM THE MID-LAKE POINT INTO CANADIAN WATERS. WINDS WILL FRESHEN AND VEER TO THE SOUTH TONIGHT AND SATURDAY AS THE SFC HIGH WILL MOVE OFF THE COAST AND A FRONTAL SYSTEM WILL START TO MAKE ITS WAY ACROSS THE UPPER GREAT LAKES. THIS COULD RESULT IN SOME WIND BASED SMALL CRAFT ADVISORIES...WITH THE HIGHEST WAVES BEING CONCENTRATED IN CANADIAN WATERS. SUNDAY WILL BE UNSETTLED ACROSS THE LOWER GREAT LAKES AS THE PASSAGE OF A COLD FRONT WILL RESULT IN THE LIKELIHOOD OF SHOWERS AND POSSIBLY A THUNDERSTORM OR TWO. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ SYNOPSIS...RSH NEAR TERM...HITCHCOCK/RSH SHORT TERM...JJR LONG TERM...JJR AVIATION...HITCHCOCK MARINE...HITCHCOCK/RSH

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