Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 280454
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
1154 PM EST SAT DEC 27 2014

.SYNOPSIS...
A LOW PRESSURE SYSTEM CROSSING FROM THE NORTHERN GREAT LAKES TO
QUEBEC WILL SWING A COLD FRONT ACROSS THE REGION TONIGHT...BRINGING
SHOWERS FOLLOWED BY MUCH COOLER TEMPERATURES ON SUNDAY. IT WILL FEEL
MUCH MORE LIKE MID-WINTER THROUGH MUCH OF THE COMING WEEK AS ARCTIC
HIGH PRESSURE BUILDS ACROSS THE GREAT LAKES.

&&

.NEAR TERM /THROUGH SUNDAY/...
WIDESPREAD RAIN SHOWERS HAVE OVERSPREAD THE WESTERN COUNTIES AS OF
04Z...AND ALTHOUGH THE RAIN IS LIGHT AT THE SURFACE THE SHOWERS WILL
BECOME A LITTLE HEAVIER AS THE LOWER ATMOSPHERE BECOME SATURATED
FROM ALOFT.

COLDER AND DRIER AIR WILL FILL IN QUICKLY BEHIND THE FRONT RESULTING
IN A SHARP CUTOFF TO THE SHOWER ACTIVITY. THERMAL PROFILES
SUGGEST THAT THERE COULD BE A MIX OR CHANGE OVER TO SNOW OVER THE
HIGHER ELEVATIONS TOWARD MORNING...BUT EXPECT LITTLE IF ANY
ACCUMULATION.

DEEP LAYER SOUTHWEST FLOW WITH A PRE-FRONTAL LOW LEVEL JET OF 50
TO 60 KNOTS WILL RESULT IN A PERIOD OF GUSTY WINDS TONIGHT. THE
STRONGEST WINDS WILL LIKELY OCCUR DOWNWIND OF THE LAKES...THEN
WINDS WILL LIKELY SLACKEN TOWARD MORNING AS THE FLOW TURNS
WESTERLY AND THE LOW LEVEL JET AXIS SHIFTS OFF TO THE EAST.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
DURING THIS PERIOD...EXPANSIVE CANADIAN HIGH PRESSURE INITIALLY
CENTERED OVER WESTERN CANADA WILL BUILD SOUTHEASTWARD ACROSS THE
ROCKIES AND INTO THE WESTERN PLAINS STATES...WITH ITS EASTERN
PERIPHERY EXPANDING ACROSS THE GREAT LAKES AND THE NORTHEAST.
PLENTY OF DRY AIR AND A LOW CAP ASSOCIATED WITH THE BURGEONING HIGH
WILL SPELL MAINLY DRY WEATHER FOR OUR AREA...SAVE FOR PERHAPS A FEW
LAKE EFFECT SNOW SHOWERS SOUTHEAST OF LAKE ONTARIO LATER SUNDAY
NIGHT/MONDAY MORNING AS MOISTURE BRIEFLY INCREASES WITH THE PASSAGE
OF A WEAK SURFACE TROUGH...THEN SOME ADDITIONAL FLURRIES MONDAY
NIGHT AND TUESDAY AS INCREASINGLY COLDER AIR CROSSES THE LOWER LAKES.

AS FOR TEMPERATURES...SLOW BUT STEADY COLD AIR ADVECTION WILL RESULT
IN READINGS FALLING BACK TO BELOW AVERAGE...WITH HIGHS IN THE UPPER
20S/LOWER 30S MONDAY DIPPING INTO THE 20S ON TUESDAY...AND LOWS IN
THE MID TO UPPER 20S SUNDAY NIGHT MOSTLY FALLING TO AROUND 20 MONDAY
NIGHT...AND EVEN COLDER EAST OF LAKE ONTARIO.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
DURING THE FIRST HALF OF THIS PERIOD...THE SPRAWLING AREA OF HIGH
PRESSURE CENTERED OVER THE WESTERN PLAINS WILL GRADUALLY BUILD EAST
TO THE CAROLINA COAST...WHILE BROAD LOW PRESSURE OVER HUDSON BAY
SLOWLY PIVOTS ACROSS NORTHERN QUEBEC AND SWINGS A WEAK SURFACE
TROUGH ACROSS NEW YORK STATE WEDNESDAY NIGHT AND THURSDAY.
TOGETHER...THESE FEATURES WILL CIRCULATE A GENERAL WESTERLY TO
WEST-SOUTHWESTERLY FLOW OF COLD AIR ACROSS OUR REGION...WITH THE
MAIN PERIOD OF MORE BACKED FLOW COMING IN CONJUNCTION WITH THE
APPROACH/PASSAGE OF THE AFOREMENTIONED TROUGH.

WHILE 850 MB TEMPS THROUGH THURSDAY NIGHT WILL ONLY SLOWLY RISE FROM
AROUND -17C TO -10C AND WILL THUS REMAIN SUFFICIENTLY COLD ENOUGH
FOR A LAKE RESPONSE...THE CURRENT MEDIUM RANGE GUIDANCE STILL
SUGGESTS THAT A RELATIVELY LOW CAPPING INVERSION WILL REMAIN IN
PLACE OVER LAKE ERIE...ALONG WITH VERY LIMITED MOISTURE AT BEST.
TOGETHER THESE FACTORS WOULD LIKELY ACT TO INHIBIT MUCH OF A LAKE
RESPONSE...AND IN TURN POPS DOWNWIND OF LAKE ERIE HAVE ACCORDINGLY
BEEN LOWERED TO BELOW THE CHANCE THRESHOLD RIGHT THROUGH THURSDAY
NIGHT. OFF LAKE ONTARIO SOMEWHAT BETTER AVAILABLE MOISTURE AND A
HIGHER CAP SHOULD ALLOW FOR AT LEAST A CHANCE OF LAKE SNOWS
THROUGHOUT...SO HAVE GENERALLY RETAINED MID TO HIGH CHANCE POPS EAST
AND NORTHEAST OF LAKE ONTARIO THROUGH THURSDAY NIGHT. OUTSIDE OF ANY
LAKE EFFECT AREAS CONDITIONS SHOULD JUST BE MAINLY DRY AND COLD...
WITH DAYTIME HIGHS AVERAGING IN THE MID-UPPER 20S AND NIGHTTIME LOWS
RANGING FROM THE MID TEENS TO LOWER 20S.

ON FRIDAY...THE CENTER OF THE SURFACE RIDGE SHOULD SLIDE OFF THE
ATLANTIC COAST WHILE ANOTHER SURFACE LOW BEGINS TO TAKE SHAPE
SOMEWHERE OVER TEXAS. THE ENSUING WARM ADVECTION REGIME ACROSS OUR
REGION AND RAPIDLY BACKING LOW LEVEL FLOW SHOULD RESULT IN ANY
LINGERING LAKE ONTARIO LAKE SNOWS QUICKLY LIFTING NORTHWARD AND
EVENTUALLY FALLING APART THROUGH THE DAY...WITH THE REMAINDER OF THE
REGION AGAIN REMAINING MAINLY DRY. WITH SOME WARMING OF OUR
AIRMASS...TEMPS SHOULD ALSO RECOVER BACK TO AROUND SEASONAL
NORMALS...WITH HIGHS REACHING TO AROUND THE FREEZING MARK.

AS WE HEAD INTO NEXT WEEKEND...THE MEDIUM RANGE GUIDANCE IS IN
GENERAL AGREEMENT ON THE NEXT STORM SYSTEM LIFTING NORTHEASTWARD
TOWARD OUR REGION...ALBEIT AT DIFFERING RATES. THIS SHOULD RESULT IN
AT LEAST SOME SEMBLANCE OF A WARMUP...ALONG WITH A RETURN OF MORE
GENERAL CHANCES OF PRECIPITATION. WITH THE STRENGTH OF THE WARMUP IN
QUESTION AT THIS DISTANT JUNCTURE...AT THIS POINT WILL JUST
INTRODUCE BROADBRUSH LOWER-END CHANCES OF RAIN AND SNOW FOR FRIDAY
NIGHT/SATURDAY...ALONG WITH TEMPS RISING TO JUST A LITTLE ABOVE
AVERAGE TO CLOSE OUT THE PERIOD.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
VFR CIGS WILL LOWER TO MVFR CIGS ACROSS THE FORECAST AREA WITH THE
APPROACH OF A COLD FRONT AND THE ASSOCIATED WIDESPREAD RAINSHOWERS.
SOUTHWEST WINDS ALONG AND AHEAD OF THE FRONT WILL VEER TO WEST WITH
FRONTAL PASSAGE...GENERALLY BETWEEN 06Z AND 10Z. WHILE THERE MAY BE
SOME IMPROVEMENT IN CIGS ACROSS LOWER ELEVATIONS BACK INTO VFR
RANGE...UPSLOPE FLOW ACROSS HIGHER TERRAIN MAY KEEP CIGS IN MVFR
THROUGH THE END OF THE PERIOD.

OUTLOOK...
SUNDAY THROUGH TUESDAY...VFR/MVFR CIGS.
WEDNESDAY AND THURSDAY...IFR IN WSW LAKE EFFECT -SHRA...MVFR/VFR
ELSEWHERE.

&&

.MARINE...
SOUTHWEST WINDS WILL CONTINUE TO FRESHEN AND VEER TO THE WEST
TONIGHT AS A COLD FRONT SWINGS ACROSS THE LAKES. THE ENSUING COLD
ADVECTION AND INCREASE IN WINDS WILL GENERATE SMALL CRAFT ADVISORY
LEVEL WINDS AND WAVES OVERNIGHT.

THE HIGHER WAVES WILL LINGER ACROSS THE EAST END OF LAKE ONTARIO
THROUGH SUNDAY AFTERNOON BEFORE SUBSIDING AS ARCTIC HIGH PRESSURE
BEGINS TO BUILD ACROSS THE LOWER GREAT LAKES. THIS WILL RESULT IN
RELATIVELY LIGHT NORTHERLY WINDS FOR THE FIRST PART OF THE COMING
WEEK BEFORE WINDS BACK TO THE SOUTHWEST AGAIN AND STRENGTHEN AGAIN
AHEAD OF ANOTHER LOW DROPPING OUT OF THE CANADIAN ARCTIC. THIS WILL
POTENTIALLY BRING ANOTHER ROUND OF SMALL CRAFT ADVISORIES BY
WEDNESDAY.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST SUNDAY FOR LEZ040-041.
         SMALL CRAFT ADVISORY FROM 3 AM TO 7 PM EST SUNDAY FOR
         LOZ043-044.
         SMALL CRAFT ADVISORY UNTIL 1 PM EST SUNDAY FOR LOZ042.
         SMALL CRAFT ADVISORY UNTIL 7 PM EST SUNDAY FOR LOZ045.

&&

$$

SYNOPSIS...TMA
NEAR TERM...TMA/WCH
SHORT TERM...JJR
LONG TERM...JJR
AVIATION...TMA/WCH
MARINE...TMA







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