Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 240939
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
439 AM EST WED DEC 24 2014

.SYNOPSIS...
DEVELOPING LOW PRESSURE OVER THE DEEP SOUTH WILL LIFT INTO THE LOWER
OHIO VALLEY BY DAYBREAK THEN RAPIDLY DEEPEN THROUGH TODAY AND
TONIGHT AS IT SHIFTS ACROSS THE CENTRAL GREAT LAKES. EXPECT
OCCASIONAL SHOWERS AND REAR RECORD MILD TEMPERATURES TODAY...BEFORE
A COLD FRONT PLOWS THROUGH THE REGION TONIGHT. THIS FRONT WILL BE
ACCOMPANIED BY A NARROW BAND OF GUSTY SHOWERS AND THUNDERSTORMS WITH
STRONG WINDS. COLDER TEMPERATURES WILL FOLLOW FOR CHRISTMAS DAY WITH
GUSTY WINDS AND SOME SNOW ACROSS THE HIGHER TERRAIN.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A FULL LATITUDE CONUS MID-LEVEL TROUGH IS IN PLACE ACROSS THE
CENTRAL STATES EARLY THIS MORNING. A SURFACE LOW IS ORGANIZING
ACROSS THE NORTHERN GULF STATES WITH WATER VAPOR IMAGERY SHOWING
PLENTIFUL MOISTURE STREAMING NORTH ACROSS THE EASTERN THIRD OF THE
COUNTY IN THE PRESENCE OF DEEP SOUTHERLY FLOW. RADAR IMAGERY ACROSS
WESTERN AND NORTH-CENTRAL NEW YORK IS SHOWING A BROAD AREA OF LIGHT
RAIN SHOWERS SHIFTING NORTHEAST. MESOANALYSIS SHOWS THESE SHOWERS
HAVE DEVELOPED IN THE PRESENCE OF PWATS RISING TO 1.1 INCHES AND
ALONG THE NOSE OF A 30-40KT 850MB JET. SOME INTERESTING CLIMO
COMPARISONS SHOW THESE PWATS ARE +4 SD ABOVE NORMAL AND ARE GREATER
THAN ALL PREVIOUS FORECASTS WITHIN A 30 YEAR CLIMATE FORECAST SYSTEM
REANALYSIS. THIS WOULD TYPICALLY FAVOR A HEAVY RAIN EVENT IN THE
PRESENCE OF SIGNIFICANT LARGE SCALE SYNOPTIC LIFT BUT THE LIFT
THROUGH TODAY IS NOT FORECAST TO BE VERY STRONG.

TWO FAVORED AREAS OF FORCING ARE EXPECTED TO BRING FOCUSED AREAS OF
PRECIPITATION TODAY. THE FIRST IS THE MODEST 30-40KT LOW LEVEL JET
OVERHEAD WHICH IS FORCING OUR CURRENT AREA OF SHOWERS. THIS IS
FORECAST TO SHIFT NORTHEAST ACROSS UPSTATE NEW YORK THROUGH THE
MORNING WITH AN AREA OF WEAK 850MB WINDS ONLY TO AROUND 20KTS
SHIFTING OVERHEAD DURING THE AFTERNOON. THIS WILL BRING A GENERAL
0.10-0.15 OF RAIN THIS MORNING WHICH IS NOT VERY IMPRESSIVE WITHIN
THE HIGH MOISTURE AIRMASS SHIFTING ACROSS OUR AREA. A BIT MORE QPF
UP TO AROUND A THIRD OF AN INCH IS EXPECTED ACROSS THE NORTH COUNTY
DUE TO THE HELP OF UPSLOPE FLOW OVER THE TUG HILL. THROUGH THE
AFTERNOON HOURS MUCH OF THE FORECAST AREA WILL PROBABLY JUST REMAIN
CLOUDY WITH LITTLE IF ANY SHOWER ACTIVITY. THE SECOND FOCUS AREA FOR
PRECIP WILL THEN NOT ARRIVE UNTIL AFTER 00Z ALONG A STRONG COLD
FRONT WHICH WILL WORK EAST ACROSS THE FORECAST AREA. LIFTED INDEX
STABILITY VALUES GO NEGATIVE WITH THE FROPA SO HAVE CONTINUED TO
MENTION THUNDERSTORMS WITH THE COLD FRONT. MORE DETAILS ON THE HIGH
WINDS IN THE SHORT TERM SECTION BELOW.

TEMPERATURES TODAY MAY CHALLENGE RECORD HIGHS. THE DEEP SOUTHERLY
FLOW WILL BOOST HIGH TEMPERATURES INTO THE 50S ACROSS MOST OF THE
AREA WITH THE EXCEPTION OF MAYBE THE TUG HILL WHERE MID TO UPPER 40S
WILL BE OBSERVED. THE ADDED BOOST OF DOWNSLOPING FROM THE HIGHER
TERRAIN ACROSS THE SOUTHERN TIER WILL BOOST TEMPERATURES ALONG THE
SOUTHERN LAKE SHORES TOWARD 60 DEGREES. CURRENT STANDING RECORD
HIGHS FOR TODAY ARE AS FOLLOWS... BUFFALO 59 SET IN 1964...
ROCHESTER 58 SET IN 1982 AND WATERTOWN 55 SET IN 1964. WINDS TODAY
WILL BE BREEZY BUT NOT NEARLY AS STRONG AS THEY WILL BE WITH THE
COLD FRONT COMING TONIGHT. GUSTS TODAY LIKELY ONLY REACHING 20-25
MPH.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
THE MAIN FOCUS DURING THIS PERIOD WILL CONTINUE TO REVOLVE AROUND A
STRONG AREA OF LOW PRESSURE MOVING THROUGH THE CENTRAL GREAT LAKES.
THIS SYSTEM WILL NOT ONLY POSE A RISK FOR DAMAGING WINDS NORTHEAST
OF THE LAKES...BUT MAY EVEN PRODUCE SEVERE WEATHER.

SYNOPTIC OVERVIEW...
A RAPIDLY DEEPENING SURFACE LOW WILL MOVE FROM LOWER MICHIGAN
THIS EVENING ACROSS LAKE HURON OVERNIGHT AND REACH WESTERN QUEBEC BY
CHRISTMAS MORNING. THE GFS/CANADIAN SOLUTIONS REMAIN ON THE FASTER
SIDE OF THE MODEL SUITE WHILE THE NAM IS THE SLOWEST. THE
INTENSIFICATION OF THIS SYSTEM WOULD TEND TO SUPPORT A LITTLE
SLOWER SOLUTION THAN THE GFS/CANADIAN...BUT PERHAPS NOT QUITE AS
SLOW OR AS INTENSE AS THE NAM. A POWERFUL COLD FRONT TRAILING THIS
LOW WILL ENTER WESTERN NEW YORK DURING THE MID TO LATE
EVENING...THEN SWEEP EAST ACROSS THE AREA OVERNIGHT. THE LOW
PRESSURE SYSTEM WILL BE CLOSE TO THE DEFINITION OF
BOMBOGENESIS...WITH 24 HOUR PRESSURE FALLS APPROACHING 24 MB. A
VERY STRONG MID LEVEL TROUGH WILL SWING THROUGH THE GREAT LAKES ON
A SIMILAR TRACK AND PROVIDE A PERIOD OF STRONG ASCENT WITHIN THE
DPVA REGION ON ITS EASTERN FLANK.

RAINFALL...
WARM AND MOIST AIR WILL ADVANCE INTO WESTERN NEW YORK AHEAD OF THE
UPPER WAVE AND COLD FRONT. PRECIPITABLE WATER VALUES ARE FORECAST TO
RISE TO OVER AN INCH. THE MOISTURE ADVECTION COMBINED WITH
INCREASING LARGE SCALE DYNAMICS WILL SUPPORT A PERIOD OF RAIN
FOCUSED ALONG THE FRONTAL ZONE. THE RAIN WILL QUICKLY END FROM WEST
TO EAST OVERNIGHT AS A SHARP DRY SLOT CROSSES THE REGION. A FEW
SHOWERS MAY MOVE BACK INTO WESTERN NEW YORK BY DAYBREAK CHRISTMAS
MORNING AS WRAP AROUND MOISTURE ARRIVES.

SEVERE POTENTIAL...
THERE IS GROWING CONCERN FOR A LINE OF SHALLOW CONVECTION WHICH MAY
DEVELOP ALONG THE COLD FRONT...AS A NARROW WINDOW OF FAVORABLE
INSTABILITY DEVELOPS. IF A CONVECTIVE LINE DOES IN FACT
DEVELOP...THE INTENSE WIND FIELDS EXISTING NEAR THE SURFACE LOW WILL
BRING THE RISK FOR DOWNDRAFTS TO POTENTIALLY PRODUCE LOCALIZED
SEVERE WIND GUSTS...WHICH COULD CAUSE A CONSIDERABLE SWATH OF
SIGNIFICANT WIND DAMAGE.

WIND POTENTIAL...
THE SURFACE LOW TRACK IS VERY CLOSE TO DOWN THE MIDDLE OF OUR
CLIMATOLOGICALLY FAVORED TRACK FOR A HIGH WIND EVENT NORTHEAST OF
LAKES ERIE AND ONTARIO. A LOOK AT THE CIPS ANALOG PAGE FROM SAINT
LOUIS UNIVERSITY PULLS UP SEVERAL NOTABLE HIGH WIND EVENTS FROM THE
PAST...INCLUDING AN EVENT FROM JANUARY OF 2008 AND DECEMBER OF 2008
WHICH BOTH PRODUCED SIGNIFICANT DAMAGING WINDS AND EVEN SEVERE
WEATHER NORTHEAST OF BOTH LAKES. THE GFS REMAINS CONSISTENT IN
SHOWING AN INTRUSION OF STRATOSPHERIC AIR WITH THE DYNAMIC
TROPOPAUSE FOLDING DOWN TO AROUND 500 MB WITHIN THE MID LEVEL DRY
SLOT...INDICATING STEEP MID LEVEL LAPSE RATES AND A BETTER POTENTIAL
FOR DEEP MIXING. ALL MODEL GUIDANCE CONTINUES TO SHOW THE CHANNEL OF
STRONGEST WINDS MOVING OVER LAKE ERIE AND CROSSING THE NIAGARA
FRONTIER...LAKE ONTARIO...AND SAINT LAWRENCE VALLEY.

LIKEWISE...THE GFS SUGGESTS THAT THE 1.5 PV SFC WILL LOWER TO AS
LOW AS 850 MB...BUT THE CORE WILL STAY JUST TO THE WEST ON THE OTHER
SIDE OF THE CANADIAN BORDER. THE GENERAL LOBE OF THIS FOLD WILL
CROSS THE WESTERN COUNTIES BETWEEN 06Z AND 12Z CHRISTMAS EVE
THOUGH...MAKING THIS THE TIME OF HIGHEST RISK FOR DAMAGING WINDS.

THE NAM REMAINS STRONGER WITH WINDS ALOFT IN THE POST FRONTAL
ENVIRONMENT...WITH JUST OVER 70 KNOTS A FEW THOUSAND FEET OF THE
DECK WHILE GFS WINDS ARE IN THE 55-60 KNOT RANGE AT THAT LEVEL...
BUT EVEN THE WEAKER GFS/ECMWF WIND FIELDS ARE STILL SUPPORTIVE OF
WARNING CRITERIA GUSTS NORTHEAST OF THE LAKES. BUFKIT MOMENTUM
TRANSFER SCHEMES ARE ALSO SUPPORTIVE OF WARNING CRITERIA GUSTS.

GIVEN THE MODEL CONSISTENCY...ANALOG SUPPORT...AND PATTERN
RECOGNITION...A HIGH WIND WARNING REMAINS IN EFFECT FROM THE LAKE
ERIE SHORE NORTHEAST ACROSS THE NIAGARA FRONTIER TO ROCHESTER AND
ALSO IN JEFFERSON COUNTY NORTHEAST OF LAKE ONTARIO. GUSTS UP TO 65
MPH WILL BE POSSIBLE NORTHEAST OF LAKE ERIE AND 60 MPH NORTHEAST OF
LAKE ONTARIO. THE REST OF THE AREA WILL BE FILLED IN WITH A WIND
ADVISORY WHERE GUSTS OF 50-55 MPH ARE LIKELY. WINDS WILL LIKELY
OCCUR FASTER THAN MODEL GUIDANCE WOULD SUGGEST...STARTING
IMMEDIATELY AFTER THE COLD FRONTAL PASSAGE LATER THIS EVENING AND
CONTINUING THROUGH CHRISTMAS DAY.

OTHERWISE FOR CHRISTMAS DAY EXPECT WRAP AROUND MOISTURE TO CROSS THE
AREA FROM WEST TO EAST WITH A FEW SHOWERS. THE BOUNDARY LAYER WILL
REMAIN QUITE MILD...SO EXPECT NOTHING MORE THAN A FEW WET SNOWFLAKES
TO MIX IN AT LOWER ELEVATIONS WITH NO ACCUMULATION. ACROSS THE
HIGHER TERRAIN OF THE WESTERN SOUTHERN THERE THERE MAY BE A COATING
TO AN INCH OF SLUSH FROM MORNING THROUGH EARLY AFTERNOON...WITH
SIMILAR AMOUNTS ACROSS THE HIGHER TERRAIN EAST OF LAKE ONTARIO
DURING THE AFTERNOON.

THURSDAY NIGHT ANY REMAINING SCATTERED SNOW SHOWERS EAST OF LAKE
ONTARIO WILL END AS DEEPER MOISTURE IS STRIPPED AWAY. WINDS WILL
QUICKLY DIMINISH AS THE PRESSURE GRADIENT RELAXES AND STRONGER WINDS
ALOFT EXIT. FRIDAY WILL THEN BE DRY WITH HIGH PRESSURE BUILDING
THROUGH THE MID ATLANTIC STATES. THERE MAY EVEN BE SOME SUNSHINE...
AND TEMPERATURES WILL CLIMB INTO THE 40S IN MOST AREAS AS 850 MB
TEMPS RECOVER TO AROUND +2C.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
ON SATURDAY A QUICK MOVING MID LEVEL TROUGH AND COLD FRONT WILL
CROSS THE AREA DURING THE AFTERNOON. IT IS QUITE MILD AHEAD OF THIS
SYSTEM WITH HIGHS IN THE 40S AGAIN...SO ANY PRECIP WILL INITIALLY BE
RAIN SATURDAY AFTERNOON. SATURDAY NIGHT MODERATE COLD ADVECTION MAY
SUPPORT SOME VERY LIMITED LIGHT LAKE EFFECT SNOW SHOWERS EAST OF
BOTH LAKES.

SUNDAY THROUGH EARLY NEXT WEEK MODEL GUIDANCE CONTINUES TO STRUGGLE
WITH THE PATTERN...WITH BOTH THE GFS AND ECMWF SHOWING WIDE SWINGS
IN RANGES OF POSSIBILITY FROM RUN TO RUN. THE GFS IS MOST BENIGN...
WITH A WEAK WAVE PASSING WELL TO OUR SOUTHEAST SUNDAY AND EARLY
MONDAY WITH A WEAK NORTHERN STREAM TROUGH POSSIBLY BRINGING A FEW
LIGHT SNOW SHOWERS AND WEAK LAKE EFFECT. THE ECMWF BRINGS A SLOWER
SOUTHERN STREAM LOW THROUGH THE OHIO VALLEY AND INTO THE NORTHEAST
ON MONDAY...WHICH IS A FULL DAY LATER THAN ITS SOLUTION FROM
YESTERDAYS 12Z RUN. GIVEN THE UNCERTAINTY WILL JUST GO WITH A LOW
CHANCE OF SNOW SHOWERS FOR NOW UNTIL BETTER MODEL AGREEMENT AND
CONSISTENCY IS SEEN. IT DOES APPEAR TO TURN COLDER EARLY NEXT WEEK
WITH TEMPERATURES DROPPING TO NEAR...OR EVEN A LITTLE BELOW AVERAGE
BY DAY 7.

&&

.AVIATION /10Z WEDNESDAY THROUGH SUNDAY/...
A WIDE SWATH OF LIGHT RAIN SHOWERS IS SHIFTING NORTHEAST ACROSS THE
REGION THIS MORNING FORCED BY A 30-40KT LOW LEVEL JET AHEAD OF A
DEVELOPING AREA OF LOW PRESSURE OVER THE DEEP SOUTH. VFR IS EXPECTED
WITH THESE SHOWERS WITH SOME POCKETS OF MVFR OR IFR ACROSS THE
SOUTHERN TIER BUT OVERALL THE SHOWERS SHOULD MAINLY ONLY HANG
ON THROUGH THE MORNING HOURS WITH A PERIOD OF DRY CONDITIONS THIS
AFTERNOON.

A STRONG COLD FRONT WILL ARRIVE LATER THIS EVENING BETWEEN 03-06Z
WITH BAND OF SHOWERS AND POSSIBLE THUNDERSTORMS. A WINDS SHIFT TO
SOUTHWEST WILL OCCUR BEHIND THE FRONT WITH WIND GUSTS UP TO 50
KNOTS. A NARROW WINDOW OF LOW LEVEL WIND SHEAR IS POSSIBLE AHEAD OF
THE FRONT THIS EVENING IF THE STRONGER WINDS ARRIVE ALOFT BEFORE
THEY DO AT THE SURFACE. LLWS HAS BEEN INCLUDED IN THE TAF.

OUTLOOK...
THURSDAY...MVFR WITH SCATTERED TO NUMEROUS RAIN AND SNOW SHOWERS AND
STRONG GUSTY WINDS.
FRIDAY...MAINLY VFR.
SATURDAY...SCATTERED RAIN SHOWERS/POSSIBLE MVFR.
SUNDAY...VFR/MVFR WITH A CHANCE OF SNOW SHOWERS.

&&

.MARINE...
A MODEST SOUTHERLY TO SOUTHEASTERLY FLOW WILL PERSIST ACROSS THE
LOWER LAKES REGION TODAY AS A SIGNIFICANT LOW DEVELOPS ACROSS THE
OHIO VALLEY. THIS LOW WILL RAPIDLY DEEPEN AND LIFT ACROSS THE
CENTRAL GREAT LAKES TOWARD JAMES BAY LATER TODAY AND TONIGHT...WITH
ITS TRAILING COLD FRONT PLOWING ACROSS THE REGION. THIS FRONT WILL
BE ACCOMPANIED BY A BAND OF SHOWERS AND POSSIBLE THUNDERSTORMS WITH
STRONG WIND GUSTS...WITH A PERIOD OF SOUTHWESTERLY/WESTERLY GALES
THEN HIGHLY LIKELY ON BOTH LAKES LATER TONIGHT AND CHRISTMAS DAY AS
COLD AIR ADVECTION HELPS TO MIX STRONGER WINDS FROM ALOFT DOWN TO
THE SURFACE. GALE WARNINGS HAVE BEEN ISSUED FOR ALL MARINE SECTIONS
WITH THE EXCEPTION OF A SMALL CRAFT ADVISORY FOR THE SAINT LAWRENCE
RIVER.

WINDS WITH THEN SUBSIDE TO SMALL CRAFT ADVISORY LEVELS FOR
CHRISTMAS DAY AS THE LOW SHIFTS ACROSS QUEBEC FURTHER AWAY FROM THE
LOWER GREAT LAKES. AN AREA OF HIGH PRESSURE BUILDS IN FOR FRIDAY
WITH WINDS AND WAVES RELAXING BELOW ADVISORY THRESHOLDS BY FRIDAY
NIGHT. ANOTHER AREA OF LOW PRESSURE WILL CUT ACROSS THE CENTRAL
GREAT LAKES OVER THE WEEKEND WITH A TIGHT PRESSURE GRADIENT BRINGING
SMALL CRAFT CONDITIONS AND POSSIBLE GALES.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...HIGH WIND WARNING FROM 8 PM THIS EVENING TO 4 PM EST THURSDAY
     FOR NYZ001>003-010>012-019-085.
     LAKESHORE FLOOD WATCH FROM THIS EVENING THROUGH THURSDAY
     AFTERNOON FOR NYZ010-019-085.
     HIGH WIND WARNING FROM 1 AM TO 7 PM EST THURSDAY FOR NYZ007.
     WIND ADVISORY FROM 1 AM TO 7 PM EST THURSDAY FOR NYZ004>006-
     008.
     WIND ADVISORY FROM 10 PM THIS EVENING TO 4 PM EST THURSDAY FOR
     NYZ013-014-020-021.
MARINE...GALE WARNING FROM 9 PM THIS EVENING TO 4 PM EST THURSDAY FOR
         LEZ020-040-041.
         GALE WARNING FROM 9 PM THIS EVENING TO 4 PM EST
         THURSDAY FOR LOZ030.
         GALE WARNING FROM MIDNIGHT TONIGHT TO 10 PM EST THURSDAY
         FOR LOZ043>045-063>065.
         GALE WARNING FROM 10 PM THIS EVENING TO 4 PM EST THURSDAY
         FOR LOZ042-062.
         SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 10 PM
         EST THURSDAY FOR SLZ022-024.

&&

$$

SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM...HITCHCOCK/RSH/TMA
LONG TERM...HITCHCOCK
AVIATION...SMITH
MARINE...SMITH







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