Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 160934
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
534 AM EDT TUE SEP 16 2014

.SYNOPSIS...
RAIN SHOWERS WILL TAPER OFF THIS MORNING WITH SUNSHINE RETURNING IN
THE AFTERNOON. AN AREA OF HIGH PRESSURE WILL BRING COOL AND DRY
CONDITIONS INTO WEDNESDAY THEN A WEAK FRONT WILL BRING A SLIGHT
CHANCE FOR RAIN SHOWERS WEDNESDAY NIGHT AND THURSDAY. HIGH PRESSURE
RETURNS FOR THE END OF THE WEEK WITH A HIGH CHANCE OF SHOWERS
POSSIBLE LATE IN THE WEEKEND AS A COMPLEX FRONTAL BOUNDARY IS
FORECAST TO CROSS OUR REGION.

&&

.NEAR TERM /THROUGH TONIGHT/...
AREA RADARS SHOW THE STEADIER RAIN SHOWERS FROM OVERNIGHT HAVE NOW
SHIFTED INTO CENTRAL NEW YORK THIS MORNING AS THE DRIVING UPPER
LEVEL SHORTWAVE TROUGH QUICKLY EXITS TO OUR EAST. SOME ISOLATED
/LIKELY LAKE ENHANCED/ SHOWERS ARE SHOWING UP OVER LAKES ERIE AND
ONTARIO AT 09Z. WITH 850MB TEMPERATURES OF AROUND +4C OVER THE WARM
LAKE WATERS THERE IS JUST ENOUGH LAKE INDUCED INSTABILITY FOR THESE
SHOWERS IN AN OTHERWISE STABLE ENVIRONMENT ON THE BACK SIDE OF THE
SHORTWAVE TROUGH. AFTER SUNRISE EXPECT DIURNAL MIXING TO DISRUPT THE
WEAK FLOW DRIVING THE SHOWERS OVER THE LAKES WITH DRIER AIR HELPING
TO CLEAR OUT SKIES BY MID AFTERNOON. THE WEAK UPSLOPE FLOW OVER THE
SOUTHERN TIER WILL KEEP CLOUDY SKIES IN PLACE THE LONGEST. COOL AIR
ALOFT WILL KEEP TEMPERATURE BELOW AVERAGE TODAY WITH HIGHS TOPPING
OUT IN THE LOW TO MID 60S.

TONIGHT HIGH PRESSURE OVER THE MIDWEST STATES WILL RIDGE EAST ACROSS
THE LOWER GREAT LAKES. EXPECT THIS TO TRAP SOME LOW LEVEL MOISTURE
BENEATH A SUBSIDENCE INVERSION SO HAVE KEPT SOME SCATTERED CLOUDS
INLAND FROM THE LAKES. OTHERWISE MAINLY CLEAR SKIES NEAR THE LAKE
SHORES. SOME PATCHY RIVER VALLEY FOG WILL AGAIN BE POSSIBLE ACROSS
THE SOUTHERN TIER. THE CLOUDS WILL HELP KEEP OVERNIGHT LOWS ON THE
WARMER SIDE WITH LOWS ONLY SLIDING BACK INTO THE LOW TO MID 40S.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
A HIGH AMPLITUDE UPPER LEVEL PATTERN WILL BE IN PLACE ACROSS NORTH
AMERICA AS WE OPEN THE PERIOD WITH A DEEP TROUGH ACROSS THE EASTERN
UNITED STATES EXTENDING FROM A POLAR LOW OVER NORTHERN QUEBEC WHILE
STRONG RIDGING WILL BE FOUND OVER THE WEST. HIGH PRESSURE AT THE
SURFACE WILL PROVIDE A SUNNY DAY FOR MUCH OF THE LOWER GREAT
LAKES...HOWEVER A POTENT SHORTWAVE DROPPING AROUND THE BASE OF THE
AFOREMENTIONED UPPER LOW WILL SHUNT A COLD FRONT SOUTH TOWARDS OUR
REGION WITH CLOUDS INCREASING ACROSS THE NORTH COUNTRY ON WEDNESDAY
AS THE COLD FRONT APPROACHES THE REGION. WHILE THE BULK OF THE DPVA
AND ASSOCIATED SHOWER ACTIVITY SHOULD REMAIN NORTH OF THE
BORDER...THERE WILL BE A CHANCE OF A FEW SPRINKLES WEDNESDAY NIGHT
AS THE SURFACE COLD FRONT SAGS SOUTH ACROSS LAKE ONTARIO.

850MB TEMPS OF +4 TO +6C WILL SUPPORT HIGHS IN THE MID 60S ACROSS
THE LOWER ELEVATIONS OF THE FORECAST AREA WHILE HIGHER ELEVATIONS OF
THE SOUTHERN TIER AND NORTH COUNTRY WILL RUN A FEW DEGREES
COOLER...IN THE LOWER 60S. FOR WEDNESDAY NIGHT...ENCROACHING CLOUD
COVER ASSOCIATED WITH THE COLD FRONT WILL KEEP TEMPERATURES LOWS IN
THE MID TO UPPER 40S ALONG THE LAKE PLAINS AND INTO THE NORTH
COUNTRY WHILE ACROSS THE SOUTHERN TIER THERE MAY BE JUST ENOUGH
SOUTHWESTERLY FLOW AHEAD OF THE APPROACHING COLD FRONT TO LIMIT
RADIATIONAL COOLING AND ONLY PRODUCE LOWS IN THE LOW TO MID 40S.

THE COLD FRONT WILL DROP SOUTH OF LAKE ONTARIO AROUND DAYBREAK
THURSDAY MORNING AND CONTINUE TO SAG SOUTH ACROSS THE FORECAST AREA
DURING THE DAY. UPSLOPE NORTHERLY FLOW OFF LAKE ONTARIO BEHIND THE
FRONT COUPLED WITH 850MB TEMPS DROPPING TO AROUND +2C WILL GENERATE
PLENTY OF STRATUS ACROSS MUCH OF WESTERN AND NORTH-CENTRAL NEW
YORK...THOUGH THE NORTH COUNTRY SHOULD SEE SUNSHINE IN THE
AFTERNOON AS IT WILL ESCAPE THE INFLUENCE OF THE LAKE. THE
COMBINATION OF COLD ADVECTION AND ABUNDANT CLOUD COVER WILL MAKE
FOR A CHILLY DAY ACROSS THE AREA WITH HIGHS ONLY EXPECTED TO TOP
OUT IN THE MID 50S.

THE CLOUD COVER SHOULD DIMINISH THURSDAY NIGHT AS THE CENTER OF
THE SURFACE HIGH PASSES TO OUR NORTH AND LOW LEVEL FLOW VEERS AROUND
TO THE EAST...PARTICULARLY EAST OF THE GENESEE VALLEY AND THE
NORTH COUNTRY. THIS CLEARING COUPLED WITH THE VERY DRY AIR
ADVECTING INTO THE REGION COULD RESULT IN THE FIRST WIDESPREAD
FREEZE OF THE SEASON ACROSS THE NORTH COUNTRY WHILE FROST MAY BE
POSSIBLE ELSEWHERE WITH THE EXCEPTIONS OF AREAS NEAR THE LAKE ERIE
AND ONTARIO SHORELINES.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
THE ARCTIC HIGH AND ASSOCIATED COLD AIR WILL MOVE OFF TO THE EAST
ON FRIDAY AS THE HIGH AMPLITUDE PATTERN OF EARLIER IN THE WEEK
BRIEFLY GIVES WAY TO A MORE ZONAL FLOW ACROSS THE NORTHERN TIER OF
THE COUNTRY. WITH THE SURFACE HIGH MOVING OFF TO OUR EAST ON
FRIDAY...INCREASING SOUTHERLY RETURN FLOW WILL ALLOW FOR
TEMPERATURES TO WARM BACK INTO THE 60S ON FRIDAY BEFORE BOOSTING
READINGS INTO THE 70S ON SATURDAY WITH AN ABUNDANCE OF SUNSHINE BOTH
DAYS THANKS TO THE ABUNDANCE OF DRY AIR ACROSS THE REGION.

A MUCH MORE COMPLEX PATTERN EVOLVES FOR THE LATTER HALF OF THE
WEEKEND INTO THE BEGINNING OF NEXT WEEK. THERE ARE ESSENTIALLY THREE
TIERS OF UPPER LEVEL ENERGY THAT WILL BE MAKING THEIR WAY ACROSS
NORTH AMERICA DURING THIS PERIOD. THE FIRST IS OVER HUDSON BAY
ASSOCIATED WITH THE POLAR VORTEX. THE SECOND IS A SHORTWAVE
TRACKING OUT OF THE NORTHERN ROCKIES WITH AN ATTENDANT SURFACE LOW
THAT MOVES INTO THE WESTERN GREAT LAKES SATURDAY. THE THIRD AND
FINAL FACTOR IS THE REMNANTS OF HURRICANE ODILE THAT WILL BE
MEANDERING ACROSS THE SOUTHERN PLAINS BY SATURDAY. TO VARYING
DEGREES THE GLOBAL MODELS PHASE ALL THREE OF THESE SYSTEMS AND BRING
THEM ACROSS EASTERN NORTH AMERICA WITH THE X-FACTOR BEING THE SPEED
AND INTENSITY OF YET ANOTHER PLAYER...A POTENT SHORTWAVE DROPPING
OUT OF THE MACKENZIE BASIN OF FAR NORTHWESTERN CANADA SATURDAY NIGHT
INTO SUNDAY. THIS PARTICULAR FEATURE MAY END UP DIGGING FAR
ENOUGH SOUTH TO GENERATE A LARGE SURFACE CYCLONE OVER WESTERN
ONTARIO ON SUNDAY...AS DEPICTED BY THE ECMWF...OR ARRIVE TOO LATE
TO DO SO AND INSTEAD REINVIGORATE THE WESTERN GREAT LAKES SURFACE
LOW AS IT LIFTS INTO WESTERN QUEBEC. THE GLOBAL GEM IS EVEN
FARTHER NORTH AND EAST WITH THIS FEATURE...HAVING IT MISS OUR
GREAT LAKES LOW ENTIRELY.

IN SPITE OF THE SIGNIFICANT DIFFERENCES IN DETAILS BETWEEN THESE
SCENARIOS...THE TIMING OF IMPACTS ON SENSIBLE WEATHER ACROSS THE
LOWER GREAT LAKES IS SURPRISINGLY SIMILAR. AFTER ONE MORE WARM AND
DRY DAY SUNDAY...SHOWERS WILL LIKELY BREAK OUT ACROSS WESTERN NEW
YORK SOMETIME SUNDAY NIGHT AS THE SURFACE/UPPER LEVEL TROUGHS
APPROACH THE AREA. GIVEN THE STRONG DYNAMICS AT WORK ALONG WITH A
DECENT RETURN FLOW OFF OF MOISTURE OFF OF THE GULF OF MEXICO AND
POTENTIAL CONTRIBUTIONS FROM WHATEVER IS LEFT FROM ODILE...WE COULD
SEE A PERIOD OF MODERATE TO HEAVY RAINFALL SUNDAY NIGHT INTO MONDAY.
A COLD FRONT WILL LIKELY CROSS THE REGION MONDAY BRINGING A
POTENTIALLY SIGNIFICANT COOL-DOWN...ALTHOUGH SIGNIFICANCE OF THIS
COOL-DOWN WILL BE A FUNCTION OF THE FINAL TRACK OF THE AFOREMENTIONED
NORTHWEST CANADIAN SHORTWAVE AND THE DEGREE TO WHICH IT ENHANCES THE
LOW OVER WESTERN ONTARIO AND SUBSEQUENT POSSIBLE OCCLUSION ACROSS
THE GREAT LAKES.

&&

.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
STEADIER RAIN HAS PASSED EAST OF THE FORECAST AREA THIS MORNING.
SOME ISOLATED LAKE ENHANCE SHOWERS ARE SHOWING UP ON RADAR ALONG
LAKE ERIE AND ONTARIO. LINGERING CLOUD COVER RANGES FROM VFR TO MVFR
THIS MORNING BUT WILL BREAK UP AND LIFT THROUGH THE MORNING HOURS.
CLOUD COVER WILL BE SLOWEST TO BREAK UP ACROSS THE SOUTHERN TIER
SITES. TONIGHT HIGH PRESSURE WILL RIDGE EAST FROM THE MIDWEST
STATES. THIS WILL TRAP ENOUGH MOISTURE FOR SOME VFR LEVEL CLOUDS
INLAND FROM THE LAKES OVERNIGHT. SOME RIVER VALLEY FOG MAY ALSO
DEVELOP ACROSS THE SOUTHERN TIER.

OUTLOOK...
WEDNESDAY THROUGH SATURDAY...GENERALLY VFR. SOME PATCHES OF MVFR
CIGS WEDNESDAY NIGHT. SOME VALLEY FOG WITH LOCALIZED IFR FLIGHT
VSBYS ACROSS THE SOUTHERN TIER EACH MORNING.

&&

.MARINE...
WESTERLY WINDS WILL INCREASE TODAY BEHIND A WEAK SURFACE TROUGH.
CONVERGENT FLOW ALONG THE SOUTHEAST LAKE ONTARIO NEAR SHORE WATERS
HAS ALLOWED A SMALL CRAFT ADVISORY TO CONTINUE BETWEEN SODUS BAY AND
MEXICO BAY OTHERWISE WINDS AND WAVES IN OTHER ZONES WILL REMAIN
BELOW CRITERIA. WINDS AND WAVES WILL GRADUALLY SUBSIDE LATE TONIGHT
INTO WEDNESDAY BEFORE BUILDING ONCE AGAIN WEDNESDAY NIGHT AS
ANOTHER WEAK COLD FRONT DROPS SOUTH OUT OF CANADA.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 2 AM EDT
         WEDNESDAY FOR LOZ044.

&&

$$

SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM...WOOD
LONG TERM...WOOD
AVIATION...SMITH
MARINE...SMITH






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