000
FXUS61 KBUF 251950
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
350 PM EDT SAT MAY 25 2013

.SYNOPSIS...
CANADIAN HIGH PRESSURE BUILDING ACROSS THE GREAT LAKES WILL BRING
MAINLY DRY AND COOL CONDITIONS FOR THE MEMORIAL DAY WEEKEND. SOME OF
THE TYPICALLY COOLER AREAS OF THE SOUTHERN TIER WILL SEE FROST EARLY
SUNDAY AND MONDAY MORNINGS. TEMPERATURES WILL QUICKLY BACK TO ABOVE
AVERAGE BY THE MIDDLE OF NEXT WEEK WITH THE NEXT CHANCE OF
THUNDERSTORMS ARRIVING BY WEDNESDAY.

&&

.NEAR TERM /THROUGH SUNDAY/...
WATER VAPOR IMAGERY THIS AFTERNOON SHOWING A MATURING CUTOFF LOW
OVER SOUTHERN NEW ENGLAND WITH A SURFACE LOW NEARBY JUST NORTH OF
CAPE COD. RADAR IMAGERY STILL SHOWING SOME LIGHT RAIN CLIPPING THE
FAR EASTERN EDGE OF THE CWA MAINLY ALONG AND EAST OF THE BLACK RIVER
VALLEY. THIS RAIN IS SHOWING SOME WESTWARD PROGRESS OVER THE PAST
HOUR...SO A FEW SHOWERS MAY SNEAK INTO EASTERN JEFFERSON AND EASTERN
OSWEGO COUNTY LATE THIS AFTERNOON. ELSEWHERE DIURNAL CUMULUS AND
STRATOCUMULUS ARE BEGINNING TO MIX OUT ACROSS THE HIGHER TERRAIN OF
THE SOUTHERN TIER AND FINGER LAKES WITH INCREASING AMOUNTS OF SUN.
NEARLY FULL SUN IS NOW APPARENT ON THE LAKE PLAINS WITH STABLE LAKE
SHADOWS SPREADING INLAND.

THE MID LEVEL LOW WILL CONTINUE TO SPIN NEARLY IN PLACE THOUGH
TONIGHT BEFORE ACCELERATING INTO THE CANADIAN MARITIMES ON SUNDAY.
SHORT TERM MODEL GUIDANCE CONTINUES TO SHOW A PERSISTENT AXIS OF
STRETCHING DEFORMATION IN THE 900-700MB LAYER OVER THE BLACK RIVER
VALLEY TONIGHT THROUGH EARLY SUNDAY. THIS COMBINED WITH NUMEROUS
LOBES OF VORTICITY ROTATING AROUND THE PARENT MID LEVEL LOW WILL
PROVIDE PERSISTENT DEEP LAYER ASCENT AND CONVERGENCE...WITH A
CONTINUATION OF LIGHT RAIN OVERNIGHT INTO EARLY SUNDAY. THE RAIN
WILL BE MOST PERSISTENT OVER THE EASTERN HALF OF LEWIS COUNTY...
WITH OCCASIONAL FORAYS INTO EASTERN JEFFERSON AND POSSIBLY EASTERN
OSWEGO COUNTY.

CLEARING SKIES AND A COLD AIRMASS WILL PROMOTE ANOTHER CHILLY
NIGHT WITH LOWS IN THE UPPER 30S TO LOWER 40S ON THE LAKE PLAINS.
THE ONLY THING PREVENTING MOST AREAS FROM GOING COLDER WILL BE A
PERSISTENT GRADIENT WIND IN THE 5-10 MPH RANGE. THE ONE EXCEPTION IS
ACROSS THE WESTERN SOUTHERN TIER...WHERE SOME OF THE MORE SHELTERED
VALLEYS WILL AT LEAST PARTIALLY DECOUPLE. THIS WILL ALLOW LOWS TO
DROP INTO THE LOWER 30S...POSSIBLY 1-2 DEGREES COOLER THAN LAST
NIGHT GIVEN LESS CLOUD COVER. THIS WILL ALLOW SOME OF THE COOLER
VALLEYS TO DIP TO NEAR 30...THUS A FREEZE WARNING HAS BEEN ISSUED
FOR THE 3 SOUTHERN TIER COUNTIES.

RAIN CHANCES WILL END DURING THE DAY SUNDAY EAST OF LAKE ONTARIO AS
THE SURFACE LOW AND MID LEVEL LOW BEGIN TO KICK OUT INTO THE
CANADIAN MARITIMES. CLOUD COVER MAY EVEN BREAK FOR A LITTLE SUNSHINE
LATE IN THE DAY. ELSEWHERE EXPECT A SIMILAR TREND TO TODAY...WITH A
FEW LAKE EFFECT CLOUDS POSSIBLE SOUTHEAST OF LAKE ONTARIO FIRST
THING IN THE MORNING... BREAKING UP WITH THE START OF DAYTIME
HEATING. SUNSHINE WILL LIKELY SELF-DESTRUCT AGAIN FOR AWHILE ACROSS
THE HIGHER TERRAIN OF THE SOUTHERN TIER AND FINGER LAKES DUE TO COLD
AIR ALOFT WITH CLOUD COVER PEAKING AROUND NOON BEFORE ONGOING MIXING
AND DRY AIR ENTRAINMENT BRING INCREASING SUN IN THE AFTERNOON.

THE AIRMASS WILL SLOWLY MODIFY WITH 850MB TEMPS GAINING A FEW
DEGREES OVER TODAY...WHICH SHOULD SUPPORT HIGHS IN THE LOWER 60S AT
LOWER ELEVATIONS AWAY FROM THE LAKESHORES...AND MID TO UPPER 50S
ACROSS HIGHER TERRAIN AND THE SOUTH SHORE OF THE LAKES.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
SUNDAY NIGHT WILL AGAIN BE CHILLY AS SURFACE HIGH PRESSURE SETTLES
SOUTHEASTWARD TOWARDS WESTERN NEW YORK. SUBSIDENCE WITH THIS FEATURE
WILL PROMOTE CLEAR SKIES AND WITH A RELAXED PRESSURE GRADIENT THIS
WILL ALLOW FOR WINDS TO GO CALM...ESPECIALLY ACROSS WNY. A SLIGHT
PRESSURE GRADIENT ACROSS THE NORTH COUNTRY WITH THE LINGERING
SURFACE LOW OVER ATLANTIC CANADA MAY KEEP A SLIGHT WIND THROUGH THE
NIGHT. WITH THE IDEAL RADIATIONAL COOLING CONDITIONS LOWS WILL FALL
DOWN INTO THE 30S...WITH FREEZING TEMPERATURES LIKELY ACROSS THE
SOUTHERN TIER...SOUTHERN ERIE AND WYOMING COUNTY. WILL ISSUE A
FREEZE WATCH FOR THE SOUTHERN TIER...SOUTHERN ERIE AND WYOMING
COUNTIES STARTING AT 11 PM SUNDAY NIGHT AS CLEAR SKIES AND LIGHT
WINDS WILL ALLOW FOR TEMPERATURES TO QUICKLY RADIATE.

WITH THE HIGH PRESSURE CAMPED OVER THE REGION MONDAY...MEMORIAL DAY
WILL BE SUNNY WITH TEMPERATURES STILL A BIT ON THE COOL SIDE...WITH
HIGHS IN THE UPPER 60S FOR MOST.

MONDAY NIGHT A FEW CLOUDS WILL START TO BUILD FROM THE WEST AS A
ELONGATED SURFACE WARM FRONT PUSHES NORTHEASTWARD. THERE IS STILL
SOME UNCERTAINTY WITHIN THE OPERATIONAL MODELS WITH THE 12Z NAM AND
RGEM A BIT FASTER WITH MOISTURE ADVECTION AND THE WARM FRONT THAN
THE 12Z GFS AND ECMWF. WILL BRING A FEW SHOWERS INTO THE SOUTHERN
TIER LATE TUESDAY...AND AS THE WARM FRONT NEARS THE REGION TUESDAY
NIGHT BRING A CHANCE FOR SHOWERS THROUGH THE NIGHT ACROSS THE
REGION. INSTABILITY IS LIMITED AHEAD OF THIS WARM FRONT AND WILL
JUST HAVE SHOWERS IN THE FORECAST THROUGH THE NIGHT WITH THE WEAK
ISENTROPIC LIFT. THE SOUTHERLY WINDS AND CLOUDS OVERNIGHT NIGHT WILL
KEEP LOWS MORE ON THE MILD SIDE...WITH TEMPERATURES DROPPING OFF
INTO THE UPPER 50S AND LOWERS 60S.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
WE WILL FINISH THE LAST FEW DAYS OF MAY AND START JUNE WITH A SUMMER
LIKE FEEL. AN UPPER LEVEL RIDGE WILL BUILD EARLY IN THE PERIOD OVER
THE EASTERN STATES ALONG WITH INCREASING SURFACE TEMPERATURES AND
HUMIDITY. THE RIDGE WILL WEAKEN SOME FRIDAY AND SATURDAY WHICH WILL
SLOW THE WARMING TREND.

FOR WEDNESDAY A WEAK WARM FRONT WILL LIFT ACROSS THE CWA. A WEAK
UPPER LEVEL SHORTWAVE CRESTING OVER THE RIDGE COMBINED WITH BUILDING
MOISTURE WILL BRING A CHANCE FOR SHOWERS AND THUNDERSTORMS THROUGH
THE DAY. AS THIS WARM FRONT LIFTS NORTHWARD THE FOCUS FOR SHOWERS
AND THUNDERSTORMS WEDNESDAY NIGHT WILL BE ACROSS THE NORTH COUNTRY
WITH A WARM AND MUGGY AIRMASS LINGERING FARTHER TO THE SOUTH.

ON THURSDAY THE UPPER LEVEL RIDGE BUILDS ACROSS THE GREAT LAKES
REGION AND THIS SHOULD LIMIT THE SHOWERS AND THUNDERSTORMS ACROSS
THE REGION.

A SHORTWAVE TROUGH DIVING SOUTHEASTWARD FROM JAMES BAY AND ACROSS
QUEBEC WILL WEAKEN THE RIDGE THURSDAY NIGHT AND INTO THE WEEKEND.
WITH THE FALLING HEIGHTS ALOFT EXPECT TEMPERATURES TO PEAK IN THE
THURSDAY-FRIDAY TIMEFRAME AND THEN A LITTLE COOLER TO START NEXT
WEEKEND...THOUGH STILL ABOVE NORMAL.

A BACK DOOR COLD FRONT WILL DROP SOUTHWARD FROM CANADA AND BRING THE
CHANCE FOR SHOWERS AND THUNDERSTORMS THURSDAY NIGHT TO THE NORTH
COUNTRY...AND WITH THE WEAK BOUNDARY REMAINING OVER THE CWA ON
FRIDAY...POSSIBLY ANOTHER POP UP STORM FRIDAY AFTERNOON. FOR NOW
WILL KEEP FRIDAY DRY AND SEE WHERE THIS BOUNDARY LINGERS. SOUTH OF
THIS BOUNDARY TEMPERATURES WILL CLIMB INTO THE LOW TO MID 80S.

ON SATURDAY AN UPPER LEVEL TROUGH WILL DROP INTO THE WESTERN GREAT
LAKES REGION. SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THIS FEATURE
WITH ACTIVITY LIKELY TO REMAIN JUST TO OUR WEST THROUGH THE DAYTIME.
HIGHS ON SATURDAY WILL BE A DEGREE OR TWO COOLER THAN FRIDAY.

&&

.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
VFR CONDITIONS WILL PREVAIL FOR THE 18Z TAF CYCLE. EXTENSIVE MID
LEVEL CLOUDS ON THE WESTERN FRINGE OF A COASTAL LOW WILL CONTINUE
ACROSS THE EASTERN LAKE ONTARIO REGION TONIGHT...ALONG WITH PERIODS
OF LIGHT RAIN ALONG AND EAST OF THE BLACK RIVER. MOST OF THIS WILL
BE LIGHT ENOUGH TO KEEP CIGS/VSBY MAINLY VFR. FARTHER WEST DIURNAL
CUMULUS AND STRATOCUMULUS DUE TO COLD AIR ALOFT WILL CONTINUE ACROSS
THE HIGHER TERRAIN OF THE INTERIOR SOUTHERN TIER AND FINGER LAKES
THROUGH LATE AFTERNOON BEFORE DISSIPATING THIS EVENING WITH THE LOSS
OF DAYTIME HEATING. THERE MAY BE SOME MINOR INCREASE IN LAKE EFFECT
CLOUDS OVERNIGHT SOUTHEAST OF LAKE ONTARIO...AND MORE DIURNAL CLOUD
COVER OVER THE HIGHER TERRAIN BUT ALL OF THIS SHOULD REMAIN VFR.

OUTLOOK...
MONDAY THROUGH TUESDAY...VFR.
WEDNESDAY...MAINLY VFR WITH A CHANCE OF SHOWERS AND THUNDERSTORMS
AND ASSOCIATED BRIEF MVFR/IFR.
THURSDAY...MAINLY VFR.

&&

.MARINE...
LOW PRESSURE NEAR CAPE COD AND HIGH PRESSURE OVER THE WESTERN LAKES
WILL RESULT IN A PERSISTENT MODERATE NW FLOW ACROSS THE LOWER LAKES
FOR THE FIRST HALF OF THE HOLIDAY WEEKEND. EXPECT SMALL CRAFT
CONDITIONS TO CONTINUE ON LAKE ONTARIO RIGHT THROUGH EARLY SUNDAY
AFTERNOON WHEN THE PRESSURE GRADIENT FINALLY BEGINS TO RELAX. ON
LAKE ERIE...WINDS WILL INCREASE AGAIN TONIGHT AND EARLY SUNDAY...
BUT WITH THE SHORT FETCH EXPECT WAVES TO BUILD TO 2-4 FEET AND JUST
SHY OF SMALL CRAFT ADVISORY CRITERIA.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...FREEZE WATCH FROM SUNDAY EVENING THROUGH MONDAY MORNING FOR
     NYZ012-019>021-085.
     FREEZE WARNING FROM 2 AM TO 8 AM EDT SUNDAY FOR NYZ019>021.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 PM EDT SUNDAY FOR LOZ042>045.

&&

$$

SYNOPSIS...HITCHCOCK
NEAR TERM...HITCHCOCK
SHORT TERM...THOMAS
LONG TERM...THOMAS
AVIATION...HITCHCOCK
MARINE...HITCHCOCK