Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 221938
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
338 PM EDT MON SEP 22 2014

.SYNOPSIS...
HIGH PRESSURE BUILDING EASTWARD FROM THE OHIO VALLEY WILL GIVE US
ONE MORE CHILLY NIGHT WITH LOWS IN THE LOWER TO MIDDLE 40S ACROSS
THE REGION. CLEARING SKIES AND MORE SUNSHINE ARE EXPECTED THROUGH
THE REST OF THE WEEK AS THE HIGH PRESSURE CELL SETTLE ACROSS NEW
YORK STATE AND THE NEW ENGLAND. THIS WILL PROVIDE WESTERN AND NORTH
CENTRAL NEW YORK WITH AN EXTENDED PERIOD OF FINE EARLY FALL
WEATHER...ALONG WITH TEMPERATURES WARMING TO ABOVE NORMAL BY MIDWEEK.

&&

.NEAR TERM /THROUGH TUESDAY/...
SKIES WILL REMAIN CLOUDY TO MOSTLY CLOUDY ACROSS THE FORECAST AREA
THIS AFTERNOON AND EVENING AS MOISTURE REMAINS TRAPPED BELOW A DRIER
SUBSIDENCE INVERSION ALOFT...LIFT AIDED BY UPSLOPE WINDS FROM THE
LAKE BASINS TO THE HIGHER INLAND TERRAIN.

NORTHWEST WINDS AND MOISTURE TRAPPED BELOW THE 5-8KFT INVERSION HAVE
COUPLED WITH UPSLOPE FLOW...850MB TEMPS NEAR 0C AND A BROAD UPPER
TROUGH TO MAINTAIN THIS LAYER OF CLOUDINESS THROUGH MUCH OF THE
DAY...BUT AN ERODING BACK EDGE TO THE CLOUD SHIELD IS EVIDENT ON
SATELLITE IMAGERY...MOVING SOUTHEASTWARD ACROSS SOUTHERN ONTARIO.
THIS CLEARING TREND WILL CONTINUE THROUGH THE NIGHT...OFFERING A
GOOD OPPORTUNITY FOR RADIATIONAL COOLING OVERNIGHT...THUS THE LOW
TEMPS IN THE LOWER TO MIDDLE 40S...WHICH WILL BE CLOSE TO THE
DEWPOINT TEMPS OVERNIGHT AS WELL. A DRIER BUBBLE OF DEWPOINTS IN THE
UPPER 30S WAS CROSSING THE REGION DURING LATE MORNING AND AFTERNOON.

TUESDAY WILL BE A WARMER DAY WITH HIGH TEMPS IN THE MID 60S TO LOWER
70S UNDER THE INFLUENCE OF MORE SUNSHINE AND A RETURN TO 850MB TEMPS
NEAR +6C TO +8C.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
A COMMANDING...BROAD BASED RIDGE WILL BE FOUND ACROSS THE ENTIRE
CONUS DURING THIS PERIOD...EFFECTIVELY PLACING A PROTECTIVE DOME OF
DRY FAIR WEATHER OVER THE COUNTRY. WHILE THIS STAUNCH FAIR WEATHER
GIANT WILL INITIALLY SPAN FROM COAST TO COAST...A TRAIN OF
SHORTWAVES RACING ACROSS THE NORTH PACIFIC WILL FEED INTO AND DEEPEN
A LONGWAVE TROUGH OFF THE PACIFIC NORTHWEST. THIS WILL BUCKLE THE
FLOW A BIT AND PROMOTE AMPLIFICATION OF THE ALREADY IMPRESSIVE
DOWNSTREAM RIDGE...SO THAT BY LATE WEEK...PROFOUND HEIGHT DEPARTURES
WILL BE FOUND JUST TO THE NORTH OF THE GREAT LAKES.

THE RESULT OF ALL OF THIS WILL BE A PROLONGED PERIOD OF DRY WEATHER
FOR OUR REGION WITH A GRADUAL DAY TO DAY WARMING TREND THAT WILL
SEND OUR TEMPERATURES TO ABOVE NORMAL LEVELS. THERE WILL NOT BE A
LOT OF DETAILS TO COVER WITHIN THIS UNUSUAL SYNOPTIC PATTERN...BUT
LETS TRY TO BREAK THIS DOWN A BIT ON A DAY TO DAY BASIS.

THE HEART OF THE STRONG SFC HIGH WILL DRIFT ACROSS NEW ENGLAND
TUESDAY NIGHT....THEN WILL BECOME ANCHORED IN THE VCNTY OF NOVA
SCOTIA ON WEDNESDAY. HOW STRONG WILL THE SFC HIGH BE? FORECAST
MSLP VALUES OF 1036-37MB WILL TRANSLATE TO LEVELS THAT ARE ONLY
EXPERIENCED IN THAT AREA/AT THAT TIME OF YEAR TO A ONCE IN 30 YEAR
RETURN INTERVAL. IN ANY CASE...THIS WILL PUT THE BRAKES ON THE
WARM ADVECTION. H85 TEMPS WILL BE HELD AROUND 10C...SO AFTER A
NIGHT OF WIDESPREAD LOWS IN THE 40S (AWAY FROM THE LAKES)...WE CAN
ANTICIPATE WEDNESDAY AFTERNOON HIGHS CLOSE TO 70 ALONG WITH A FAIR
AMOUNT OF SUN.

ON THURSDAY...A WEAKNESS IN THE HGT FIELD OVER THE MID ATLANTIC
STATES WILL BE BLOCKED FROM ADVANCING NORTHWARDS BY RIDGING OVER THE
GREAT LAKES WHILE AT THE SFC STRONG HIGH PRESSURE WILL EXTEND FROM
THE GREAT LAKES FROM JUST SOUTH OF NOVA SCOTIA. THE ASSOCIATED
SUBSIDENCE FROM THE LATTER AND AMOUNT OF DRY AIR IN PLACE WILL ONCE
AGAIN PROMOTE PRTLY/MSTLY SUNNY SKIES WITH A GENEROUS COVERING OF
MAX TEMPS IN THE LOWER 70S. IN FACT...THE WARMER VALLEYS COULD REACH
75.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
YOU WILL NOT FIND THE MEDIUM RANGE GUIDANCE IN MUCH BETTER AGREEMENT
THAN YOU WILL DURING THIS PERIOD AS BOTH THE ECMWF AND GFS BASED
ENSEMBLES CONTINUE TO BE IN LOCK STEP AGREEMENT OF DEPICTING A VERY
ROBUST...DOMINEERING H5 RIDGE OVER THE THE EASTERN HALF OF NORTH
AMERICA. THE HEART OF THE 588DM RIDGE WILL BE CENTERED OVER THE
GREAT LAKES REGION WITH 2-3 STD HGT DEPARTURES FOUND ACROSS A LARGE
PORTION OF EASTERN CANADA. ANOTHER WAY TO SPIN THE NUMBERS FOR THIS
FEATURE IS THAT THE STRENGTH OF THIS RIDGE HAS A RETURN (OCCURRENCE)
INTERVAL (FOR THIS TIME OF YEAR) OF ROUGHLY ONCE IN A >30 YEAR
PERIOD. THIS UPPER LEVEL PATTERN WILL SUPPORT A SUBSIDENCE CRUSHING
AREA OF HIGH PRESSURE THAT WILL ENCOMPASS THE GREAT LAKES REGION AND
VIRTUALLY GUARANTEE DRY WEATHER.

MEANWHILE...H85 TEMPS WILL RANGE FROM AROUND 10C ON FRIDAY TO
BETWEEN 12 AND 14C FOR BOTH DAYS OF THE WEEKEND. THIS WILL RESULT IN
ABOVE NORMAL TEMPERATURES FOR OUR FORECAST AREA WITH DAYTIME HIGHS
IN THE 70S AND OVERNIGHT LOWS MAINLY IN THE 50S. THESE VALUES WILL
BE SOME 5 TO 10 DEG F ABOVE NORMAL LATE SEPT VALUES.

&&

.AVIATION /20Z MONDAY THROUGH SATURDAY/...
NORTHWESTERLY UPSLOPE FLOW MAINTAINS WIDESPREAD MVFR CIGS ACROSS OUR
REGION. HIGH PRESSURE AND DRIER AIR WILL GRADUALLY BUILD INTO THE
REGION. A CLEARING LINE ACROSS SOUTHERN ONTARIO IS SLIPPING
SOUTHEASTWARD AND WILL CLEAR SKIES ACROSS THE REGION OVERNIGHT. SOME
VALLEY FOG WILL FORM AND MAY AFFECT KJHW WITH FOG LATE TONIGHT AND
AGAIN ON TUESDAY NIGHT.

OUTLOOK...
TUESDAY THROUGH FRIDAY...VFR...EXCEPT FOR LOCALIZED IFR IN SOUTHERN
TIER VALLEY FOG EACH OVERNIGHT/EARLY MORNING.

&&

.MARINE...
NORTHWESTERLY WINDS WILL SHIFT TO WEST AND WEAKEN TONIGHT AS HIGH
PRESSURE BUILD ACROSS THE LOWER LAKES. SMALL CRAFT ADVISORIES WILL
REMAIN IN EFFECT THIS EVENING ALONG THE SOUTH SHORE OF LAKE ONTARIO.

EXPANSIVE HIGH PRESSURE WILL SETTLE ACROSS THE LOWER GREAT
LAKES ON TUESDAY...THEN WILL LINGER IN PLACE RIGHT THROUGH NEXT
WEEKEND. THIS WILL RESULT IN AN EXTENDED PERIOD OF TRANQUIL
CONDITIONS.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT TUESDAY FOR LOZ043>045.
         SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR
         LOZ042.

&&

$$

SYNOPSIS...WCH
NEAR TERM...WCH
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...WCH
MARINE...WCH






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