FXUS61 KBUF 130903
AFDBUF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
403 AM EST SAT MAR 13 2010
.SYNOPSIS...
A BROAD AREA OF LOW PRESSURE OVER THE OHIO VALLEY AND MID ATLANTIC
STATES WILL CIRCULATE AN EASTERLY FLOW OF MOISTURE FROM THE ATLANTIC
ACROSS THE REGION THROUGH THE WEEKEND. THE LOW IS EXPECTED TO SLOWLY
MOVE JUST OFF THE MID ATLANTIC COAST SUNDAY AFTERNOON AND NIGHT.
GRADUAL IMPROVEMENT IS EXPECTED MONDAY AS THE SYSTEM MOVES OUT TO
SEA...WITH DRIER AND RELATIVELY MILD WEATHER TO FOLLOW FOR MOST OF
NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
THIS PERIOD WILL HAVE A FEW CHALLENGES TO DEAL WITH AS LOW PRESSURE
CENTERED OVER VIRGINIA WILL PRODUCE A BRISK EASTERLY FLOW OF
ATLANTIC MOISTURE ACROSS A GOOD SHARE OF OUR CWA. THE PROJECTED 850
MB EASTERLY COMPONENT WINDS ARE EXPECTED TO BE 4 TO 5 STANDARD
DEVIATIONS ABOVE NORMAL. THE NOSE OF THE 850 MB JET WILL LIE RIGHT
ACROSS THE SOUTHERN AND WESTERN PARTS OF OUR CWA. THIS WILL LEAD TO
PLENTY OF LIFT AND HIGH PROBABILITIES OF RAIN. THE NORTH COUNTRY
WILL BE NORTH OF THE LIFTING MECHANISM MUCH OF TODAY. WE WILL HAVE
LOWER POPS THERE BUT BUMP THEM UP TONIGHT AS THE 850 JET MOVES A
LITTLE FURTHER NORTHWARD.
ALTHOUGH QPF IS NOT AS IMPRESSIVE AS EARLIER...THERE IS STILL ENOUGH
OF A POTENTIAL TO KEEP THE FLOOD WATCH IN TACT FOR THE AREAS IT WAS
PUT UP FOR YESTERDAY. FROM THE LOOKS OF THE MODELED SNOW WATER
EQUIVALENT MAP FROM THE NATIONAL OPERATIONAL HYDROLOGIC REMOTE
SENSING CENTER...THE AREAL COVERAGE OF THE SNOWPACK THAT HAS BETWEEN
2 AND 6 INCHES OF WATER IN IT HAS SHRUNK SIGNIFICANTLY TO JUST THE
VERY HEADWATERS OF THE BUFFALO AREAS CREEKS. THIS WILL MEAN A SLOWER
AND LESS OF A WATER RELEASE THAN WE HAVE HAD THE LAST THREE DAYS.
TEMPERATURES WILL BE COOLER TOO.
DYNAMIC COOLING OF THE AIR CIRCULATING AROUND THE LOW ACTUALLY GIVES
SOUNDINGS THAT WOULD FAVOR WET SNOW MIXING IN ACROSS THE HIGHER
ELEVATIONS OF CATTARAUGUS AND ALLEGANY COUNTIES LATE TONIGHT. WE
WILL PUT IN JUST MINOR ACCUMULATIONS UNDER ONE HALF INCH. THIS OF
COURSE WILL HAVE TO BE MONITORED. WE WILL KEEP OVERNIGHT LOWS ABOVE
FREEZING.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
THE CORE OF THE UPPER LOW WILL BE CENTERED OVER THE MOUTH OF
CHESAPEAKE BAY ON SUNDAY MORNING AND THE SURFACE LOW WILL BE
STARTING TO FILL UNDER THE UPPER LOW. BOTH GFS AND ECMWF ARE SHOWING
A COASTAL LOW FORMING AT THE EXPENSE OF THE LANDBOUND LOW...AND A
DRY SLOT CUTTING BETWEEN THE UPPER LOW AND THE COASTAL LOW. THIS
DEVELOPING PATTERN WILL ALSO SHUNT THE 850MB MOISTURE-LADEN JET
FARTHER UP THE NEW ENGLAND COAST AND AWAY FROM NEW YORK STATE DURING
SUNDAY EVENING AND NIGHT. WILL HAVE A DIMINISHING TREND IN THE
CATEGORICAL POPS ON SUNDAY...SHRINKING FROM WEST TO EAST AND LEAVING
ONLY SLIGHT CHANCE POPS BY EARLY MONDAY MORNING. THERE WILL BE
ENOUGH RESIDUAL MOISTURE TO YIELD ABOUT A QUARTER INCH OVER MUCH OF
THE FORECAST AREA DURING SUNDAY...THEN A SHARP CUTOFF IN MOISTURE
FOR SUNDAY NIGHT. COLD AIR WRAPPED AROUND THE UPPER LOW CLOUD
PRODUCE SOME WET SNOW OVER THE HIGHER ELEVATIONS OF THE SOUTHERN
TIER VERY EARLY SUNDAY MORNING...AND AGAIN TRACE AMOUNT OF WET SNOW
IN THE SAME LOCATIONS EARLY SUNDAY NIGHT. ANY ACCUMULATION WILL BE
LESS THAN AN INCH...IF IT ACCUMULATES AT ALL.
TEMPS ON SUNDAY WILL BE SUPPRESSED BY THE PRECIP AND THE COLDER AIR
ALOFT ASSOCIATED WITH THE UPPER LOW. WILL HAVE HIGHS IN THE UPPER
30S TO THE LOWER 40S...SURPRISINGLY THE WARMER TEMPS IN THE MID 40S
WILL BE ACROSS THE NORTH COUNTRY WHERE NORTHEAST WINDS WILL TAP INTO
WARMER AIR OVER THE LOWER SAINT LAWRENCE VALLEY.
ON MONDAY, EXPECT DRIER AIR TO SPREAD SOUTHEAST DURING THE DAY AS
HIGH PRESSURE BUILDS EAST ACROSS THE GREAT LAKES...THIS DRY TREND TO
CONTINUE THROUGH MUCH OF THE WEEK.
TEMPS IN MONDAY WILL BE IN THE MIDDLE 40S TO LOW 50S AS THE PRECIP
COMES TO AN END...THE CLEARING SKIES AND DRIER AIR WILL ALLOW TEMPS
TO DROP TO THE MID 20S TO LOW 30S ON MONDAY NIGHT. SUNNY SKIES WILL
ALLOW TEMPS TO CLIMB TO THE LOWER TO MID 50S ON TUESDAY...TEMPERED
BY THE NORTHERLY WIND.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
THIS PERIOD STILL LOOKS TO BE VERY PLEASANT ON BOTH THE GFS AND
ECMWF AS LARGE SFC HIGH SETS UP ACROSS THE GREAT LAKES REGION AS
UPPER LEVEL TROFFING SETS UP WELL TO OUR EAST. 850 TEMPS AVERAGE
AROUND ZERO TO +2C THROUGH MUCH OF THE PERIOD...SO LOOK FOR MAX
TEMPS IN THE MID 40S TO LOWER 50S AND MINS 25-35...STILL SLIGHTLY
ABOVE NORMAL AS MARCH RETURNS TO ITS LAMBLIKE WAYS. 00Z ECMWF SWINGS
A WEAK BACK DOOR COLD FRONT DOWN ACROSS THE REGION THURSDAY NIGHT
AND FRIDAY MORNING BUT MOISTURE IS VERY LIMITED AND ONLY SEE SLGT
CHC POPS AT BEST FOR A LIMITED PORTION OF THE REGION.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
LOW PRESSURE CENTERED OVER THE NORTH CAROLINA WILL LIFT SLOWLY TO
THE NORTH AND REACH NORTHERN VA BY SATURDAY EVENING. MOIST ATLANTIC
AIR SURGING AHEAD OF THE WILL GENERATE PERIODS OF MORE STEADY RAIN
LATER TONIGHT THROUGH SATURDAY. VFR CONDITIONS WILL PREVAIL AT MOST
TAF SITES UNTIL THE STEADIER RAIN ARRIVES ON SATURDAY AND CAUSES
CIGS AND VSBYS TO LOWER TO MVFR ACROSS MOST OF WESTERN NY AND THE
GENESEE VALLEY. IFR CIGS ARE EXPECTED ACROSS THE SOUTHERN TIER WITH
THE MOIST EASTERLY UPSLOPE FLOW. SINCE THE STEADIEST RAIN IS
EXPECTED TO REMAIN SOUTH OF KART...VFR CONDITIONS ARE EXPECTED AT
THIS SITE THROUGH THE TAF PERIOD.
LLWS WILL ALSO REMAIN A CONCERN THROUGH TONIGHT AS A 50 TO 60 KNOT
LOW LEVEL JET TRACKS WEST ACROSS NEW YORK LLWS MAY STILL IMPACT THE
TAF SITES ON SATURDAY...ESPECIALLY IF THE STRONGER GUSTS ALOFT
CANNOT PENETRATE THE STEEP LOW LEVEL INVERSION.
OUTLOOK...SATURDAY NIGHT AND SUNDAY...IFR WITH PERIODS OF RAIN.
MONDAY...MVFR/VFR. CHC OF SHWRS.
TUESDAY AND WEDNESDAY...MAINLY VFR.
&&
.MARINE...
WILL CONTINUE SMALL CRAFT ADVISORIES ON THE WESTERN END OF LAKE
ONTARIO TONIGHT AND WILL CONTINUE GALE WARNINGS FOR TODAY AND
TONIGHT OVER THE WESTERN HALF OF LAKE ONTARIO AS STRONG EASTERLY
WINDS CONTINUE THROUGH THIS PERIOD. SMALL CRAFT ADVISORIES HAVE ALSO
BE EXPANDED TO THE REST OF THE SOUTH SHORE OF LAKE ONTARIO SATURDAY
AND SATURDAY NIGHT.
&&
.HYDROLOGY...
AS OF THIS WRITING THE FORECASTS FOR RAIN AMOUNTS HAVE DIMINISHED
A BIT FROM EARLIER BUT WE STILL HAVE A GOOD POTENTIAL FOR A GOOD
SOAKING. 48 HOUR QPF AMOUNTS ARE OVER AN INCH FOR MUCH OF THE
FINGER LAKES REGION AND THE WESTERN AND SOUTHERN COUNTIES. RECENT
SNOWMELT HAS PRIMED EVERYTHING SO THE ADDITIONAL RUNOFF FROM
RAINFALL WILL CAUSE FURTHER RISES OVER SLOWER RESPONDING STREAMS
SUCH AS THE TONAWANDA AND ELLICOTT CREEKS AND THE ALLEGHENY RIVER.
FASTER STREAMS ARE FALLING AS OF 4 AM. NEW RISES FROM RAINFALL
WILL LIKELY REMAIN BELOW FLOOD STAGE BUT WE WILL MONITOR FOR
POSSIBLE WARNING ISSUANCES. THE FLOOD WATCH WILL CONTINUE WHERE
IT IS ALREADY IN PLACE.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...FLOOD WATCH FROM 7 AM EST THIS MORNING THROUGH SUNDAY
AFTERNOON FOR NYZ010-019>021-085.
MARINE...GALE WARNING FROM 7 AM EST THIS MORNING TO 6 AM EDT SUNDAY FOR
LOZ042-062.
SMALL CRAFT ADVISORY FROM 7 AM EST THIS MORNING TO 6 AM
EDT SUNDAY FOR LOZ043-044.
SMALL CRAFT ADVISORY UNTIL 7 AM EST THIS MORNING FOR
LOZ042.
&&
$$
SYNOPSIS...WCH
NEAR TERM...SAGE
SHORT TERM...WCH
LONG TERM...JJP
AVIATION...TJP
MARINE...WCH
HYDROLOGY...SAGE
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