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000
FXUS61 KBUF 210556
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
156 AM EDT MON APR 21 2014

.SYNOPSIS...
HIGH PRESSURE WILL REMAINED RIDGED ALONG THE NORTHEAST COASTLINE
TODAY AND CONTINUE TO BRING FAIR WEATHER...WITH TODAY FEATURING A
LITTLE MORE WARMTH AND CLOUD COVER THAN SUNDAY. CLOUDS WILL THICKEN
TONIGHT WITH RAIN SHOWERS LIKELY REACHING WESTERN NEW YORK BY
DAYBREAK. A COLD FRONT WILL PASS ACROSS THE EASTERN GREAT LAKES
REGION TUESDAY SPREADING THESE RAIN SHOWERS EASTWARD...WITH COOLER
AIR FOLLOWING.

&&

.NEAR TERM /THROUGH TODAY/...
HIGH PRESSURE WILL CONTINUE TO DRIFT OFF AND AWAY FROM THE NORTHEAST
COAST. MEANWHILE...A FEW WEAK MID LEVEL SHORTWAVES WILL TRAVERSE THE
WESTERLY FLOW ALOFT THROUGH SOUTHEAST CANADA...AND COMBINE WITH
INCREASING MID LEVEL WARM ADVECTION AND MOISTURE TO PRODUCE A FEW
MID/HIGH CLOUDS OVERNIGHT. THE CLOUDS WILL BE MORE PREVALENT NEAR
THE CANADIAN BORDER. EXPECT LOWS IN THE LOWER TO MID 40S ON THE LAKE
PLAINS WITH MID 30S IN THE COOLER SOUTHERN TIER VALLEYS AND LEWIS
COUNTY. SOUTHWEST RETURN FLOW WILL INCREASE SOME OVERNIGHT...SO
EXPECT TEMPERATURES TO RISE LATE TONIGHT AS MIXING AND LOW LEVEL
WARM ADVECTION INCREASE.

ON MONDAY ONGOING DEEP SOUTHWEST FLOW AND WARM ADVECTION WILL BOOST
850MB TEMPS TO AROUND +9C BY MID AFTERNOON ACROSS WESTERN NY AND
ABOUT +7C ACROSS THE NORTH COUNTRY. WE HAVE NOTICED OVER THE PAST
SEVERAL YEARS THAT WARM AIRMASSES DURING THE PRE GREEN-UP STAGE OF
SPRING WILL OFTEN DELIVER WARMER TEMPERATURES THAN FORECAST BY MODEL
GUIDANCE...DUE TO LACK OF TRANSPIRATION FROM PLANTS AND TREES. WITH
THIS IN MIND HAVE GONE ABOVE EVEN THE WARMEST GUIDANCE...WITH HIGHS
IN THE MID 70S AT LOWER ELEVATIONS AWAY FROM LAKE INFLUENCES...WITH
MID TO UPPER 60S EAST OF LAKE ONTARIO. SOME OF THE WARMER LOCATIONS
OF THE GENESEE VALLEY MAY REACH THE UPPER 70S.

GRADIENT ONSHORE FLOW WILL KEEP THE LAKE ERIE SHORE COOLER AND ALSO
AREAS NORTHEAST OF LAKE ONTARIO COOLER. MESOSCALE MODEL GUIDANCE
SUCH AS OUR 6KM WORKSTATION WRF SUGGEST THE SYNOPTIC SCALE SOUTHWEST
FLOW WILL NOT BE QUITE STRONG ENOUGH TO PREVENT A LAKE BREEZE FROM
DEVELOPING ALONG PORTIONS OF THE SOUTH SHORE OF LAKE ONTARIO. THIS
APPEARS MOST LIKELY FROM MONROE COUNTY EAST TO OSWEGO COUNTY WHERE
THE SYNOPTIC FLOW IS A LITTLE WEAKER...SO HAVE GONE WITH COOLER
TEMPS ALONG THE LAKESHORES OF THOSE COUNTIES.

FINALLY...THERE MAY BE TWO SMALL AREAS WHERE WINDS BECOME A LITTLE
BREEZY TOMORROW...DUE TO MORE UNIQUE MESOSCALE PROCESSES OF THE
GREAT LAKES. BUFKIT PROFILES SUGGEST 20-25 KNOTS OF WIND A FEW
THOUSAND FEET OF THE DECK. THESE STRONGER WINDS WILL NOT IMPACT
LAKES ERIE OR ONTARIO...WHERE A DOME OF COOLER AND STABLE LAKE AIR
WILL RESULT IN MUCH LIGHTER SURFACE WINDS. IMMEDIATELY DOWNWIND OF
THESE STABLE LAKE DOMES...THE STRONGER WINDS WILL ESSENTIALLY
DOWNSLOPE OFF THE STABLE LAKE DOMES...FOLLOWING ISENTROPIC SURFACES
TO THE SURFACE. THIS OFTEN PRODUCES SMALL CORRIDORS OF SOMEWHAT
STRONGER WINDS FROM ABOUT THE BUF AIRPORT NORTHEAST INTO GENESEE
COUNTY...AND ALSO ACROSS CENTRAL AND NORTHEAST JEFFERSON COUNTY.
WINDS MAY GUST TO AROUND 20 KNOTS IN THESE TWO AREAS ON MONDAY.

&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
CLOUDS WILL THICKEN AND LOWER MONDAY NIGHT WITH RAIN SHOWERS
ADVANCING TOWARD WESTERN NEW YORK AS A MID-LEVEL TROUGH AMPLIFIES
WHILE SHIFTING EAST ACROSS THE WESTERN GREAT LAKES. AHEAD OF THIS
AMPLIFYING TROUGH SURFACE LOW PRESSURE WILL SHIFT EAST ACROSS THE
LOWER LAKES AND DEEPEN. SOUTHWESTERLY WINDS AHEAD OF THE LOW AND
THICKENING CLOUD COVER WILL KEEP MILD TEMPERATURES OVERNIGHT RANGING
IN THE MID TO UPPER 40S.

TUESDAY MORNING A COLD FRONT EXTENDING SOUTH FROM THE LOW WILL CROSS
WESTERN AND CENTRAL NEW YORK BRINGING RAIN SHOWERS. SOUTHWESTERLY
MOISTURE TRANSPORT VECTORS JUST AHEAD OF THE FRONT WILL INCREASE
PWATS TO JUST OVER ONE INCH WHICH IS ABOUT +1.5SD FOR MID TO LATE
APRIL CLIMO SO HEAVY RAINFALL IS NOT EXPECTED. QPF IS A LITTLE
HIGHER WITH 12Z RUNS AND IS EXPECTED TO RANGE 0.20-0.40 INCHES. WEAK
NORTHWEST MOISTURE TRANSPORT OFF THE LAKES COMBINED WITH COLD AIR
ADVECTION AND A TRAILING SURFACE TROUGH WILL KEEP CHANCES FOR
SCATTERED RAIN SHOWERS IN THE FORECAST BEHIND THE COLD FRONT THROUGH
THE REMAINDER OF THE DAY AND INTO TUESDAY NIGHT. THE THICK CLOUD
COVER AND SHOWERS WILL KEEP TEMPERATURES A BIT COOLER THAN
PREVIOUS DAYS WITH HIGHS ONLY RANGING IN THE LOW TO MID 50S.
OVERNIGHT TUESDAY BUFKIT PROFILES CONTINUE TO SHOW WEAK SYNOPTIC
LIFT AND LOW LEVEL MOISTURE REMAINING LIKELY ASSOCIATED WITH THE
TRAILING SURFACE TROUGH WHICH WILL CONTINUE CHANCES OF SHOWERS.
OVERNIGHT LOWS WILL FALL BACK INTO THE MID 30S WITH LOWER 30S FOUND
ACROSS THE INTERIOR SOUTHERN TIER AND TUG HILL. THIS BRINGS A
POSSIBILITY OF SOME SNOW FLAKES MIXING WITH ANY LINGERING RAIN
SHOWERS ACROSS THE HILL TOPS.

WEDNESDAY INTO WEDNESDAY NIGHT MODIFIED ARCTIC SOURCED HIGH PRESSURE
WILL SETTLE ACROSS THE GREAT LAKES REGION. LINGERING CLOUD COVER
WILL BE AROUND EARLY WEDNESDAY BUT MID-LEVEL DRYING AND SUBSIDENCE
ASSOCIATED WITH THE HIGH PRESSURE WILL WORK TO CLEAR OUT SKIES WITH
FULL SUNSHINE BREAKING OUT BY THE AFTERNOON HOURS AND CLEAR SKIES
OVERNIGHT. 850MB TEMPS AROUND -5C WILL LIMIT DIURNAL HEATING AND
KEEP OUR SURFACE HIGH TEMPS LIMITED TO ONLY THE MID TO UPPER 40S
DESPITE FULL SUNSHINE DEVELOPING IN THE AFTERNOON. CLEAR
SKIES...LIGHT WINDS AND A DRIER AIRMASS WILL HELP OVERNIGHT TEMPS TO
FALL INTO THE LOW TO MID 30S WITH A POSSIBLE THREAT OF PATCHY FOG
EARLY THURSDAY MORNING.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
A PROGRESSIVE MID-LEVEL FLOW IS FORECAST FOR LATE IN THE WEEK WITH A
LOW AMPLITUDE TROUGH ACROSS THE WEST COAST WHICH WILL BUILD A RIDGE
OVER THE GREAT LAKES. ALL 20/12Z MODEL PACKAGES ARE IN FAIR
AGREEMENT THAT THE GREAT LAKES RIDGE WILL QUICKLY SHIFT OFF THE EAST
COAST ON FRIDAY BEING REPLACED BY AN EXTENDED PERIOD OF TROUGHINESS
INTO THE WEEKEND. THE LATE WEEK RIDGING AND SURFACE HIGH PRESSURE
WILL BRING DRY WEATHER ON THURSDAY WITH TEMPERATURES RECOVERING BACK
UP TO NEAR LATE APRIL NORMALS.

THURSDAY NIGHT AND FRIDAY THE WESTERN TROUGH BUILDS ACROSS THE
WESTERN GREAT LAKES AND CENTERS OVER THE LOWER GREAT LAKES. IN A
SIMILAR PATTERN TO WHAT WE WILL SEE ON TUESDAY...A SURFACE LOW AND
COLD FRONT WILL CROSS WESTERN AND CENTRAL NEW YORK BRINGING ANOTHER
ROUND OF RAIN SHOWERS. A WARM AND MOIST SOUTHWEST AND WEST FLOW WILL
HELP BOOST TEMPS ABOVE NORMAL WITH THE LEADING BAND OF RAIN SHOWERS
FRIDAY. THIS WILL KEEP MID OVERNIGHT LOW TEMPS IN THE 40S ACROSS
WESTERN NY BUT THE WARM AND MOIST AIR WILL NOT QUITE REACH THE
EASTERN LAKE ONTARIO REGION WHERE LOWS WILL STILL DIP INTO THE 30S.
HIGHS FRIDAY WILL CLIMB INTO THE LOW TO MID 60S FOR MUCH OF THE AREA
BUT A LITTLE COOLER EAST OF LAKE ONTARIO.

FRIDAY NIGHT THROUGH SUNDAY A NOW SLOWER MOVING MID-LEVEL TROUGH OF
COOL AIR WILL KEEP UNSETTLED WEATHER OVER NEXT WEEKEND. CHANCES OF
SHOWERS AND NEAR TO SLIGHTLY BELOW NORMAL TEMPERATURES ARE FORECAST
FOR SATURDAY AND SUNDAY AS NORTHWEST FLOW WILL KEEP REINFORCING COLD
ADVECTION ACROSS THE GREAT LAKES REGION. SATURDAY NIGHT TEMPERATURES
MAY DROP TO NEAR OR JUST BELOW FREEZING ESPECIALLY ACROSS INLAND
LOCATIONS AND HILLTOPS WITH A CHANCE FOR SOME SNOW AND RAIN SHOWERS
OVERNIGHT.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AT 06Z VFR FLIGHT CONDITIONS WERE FOUND AND THESE CONDITIONS ARE
EXPECTED TO PERSIST THROUGH THE TAF CYCLE. SOUTHWEST WINDS
TODAY...MAY OCCASIONALLY TOP 10 KNOTS...THEN WEAKEN SOME THIS
EVENING AND OVERNIGHT WHILE SLIGHTLY BACKING AHEAD OF A COLD FRONT.
SOME MID AND HIGH LEVEL CLOUDS WILL PASS ACROSS THE TAF SITES FROM
TIME TO TIME THROUGH THE TAF CYCLE.

OUTLOOK...
TUESDAY...AREAS OF MVFR WITH SHOWERS...IMPROVING TO VFR LATE.
WEDNESDAY...A CHANCE OF A RAIN OR SNOW SHOWER WITH MVFR
EARLY...OTHERWISE VFR.
THURSDAY...VFR.
FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.

&&

.MARINE...
SURFACE HIGH PRESSURE WILL CONTINUE TO DRIFT OFF AND AWAY FROM THE
NORTHEAST COAST THROUGH MONDAY AND REMAIN NEAR ENOUGH TO KEEP RELATIVELY
LIGHT WINDS OVER THE LOWER LAKES. THE COLD LAKE WATERS WILL ALSO
STABILIZE THE AIR OVER THE LAKES WITH LIGHTER WINDS DURING THE
AFTERNOON THAN OVER LAND AREAS. LOCAL LAKE BREEZES WILL PRODUCE
ONSHORE WINDS AGAIN MONDAY AFTERNOON.

A COLD FRONT WILL CROSS THE REGION FROM WEST TO EAST TUESDAY
MORNING. WINDS WILL INCREASE BEHIND THIS FRONT WITH CONDITIONS
POSSIBLY APPROACHING SMALL CRAFT ADVISORY CRITERIA ON LAKE ONTARIO
TUESDAY NIGHT AND WEDNESDAY.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...THOMAS
NEAR TERM...AR/HITCHCOCK
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...THOMAS
MARINE...AR/HITCHCOCK