Flash Flood Warning 38, NWS Albany, NY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
1100 AM EST MON OCT 27 2003

WORKZONES AND ISC GRIDS AVAILABLE.

.DISC...NEED AN UPDATE SINCE TEMPERATURES ARE IN MANY
INSTANCES...HIGHER THAN WHAT WE HAVE FORECASTED. WILL GO WITH
CURRENT TEMPS AND CALL TEMPS HOLDING (AS OPPOSED TO HIGHS). FRONTAL
ZONE IS JUST TO THE WEST OF A KALB...KMSV LINE AND WILL LIKELY STAY
THAT WAY FOR AT LEAST A FEW HOURS. THEN...AS LOW
PRESSURE...CURRENTLY OVER EASTERN PA MOVES BY TO THE NE OF
KALB...THE FRONT WILL BE DRAGGED TO OUR EAST. DRY SLOT IS MOVING UP
THE HUDSON SO WILL CALL IT OCCASIONAL RAIN FROM THERE ON WEST.
MESO-ETA INDICATES THAT HEAVIER RAIN STAYS WEST OF KALB THROUGH
EARLY AFTERNOON...WHERE FLOODING ALREADY IMMINENT IN SECTIONS OF
ULSTER COUNTY. HEAVIER RAIN LOOKS TO PIVOT EAST WITH THE FRONT...AND
HIT OUR EASTERN ZONES CLOSER TO 00Z TUESDAY. HUGE WRKETA HOURLY QPF
AMOUNTS LOOKS REALLY SUSPECT IN THE VICINITY OF ALBANY FOR LATER
TODAY. FOLLOWED MESO-ETAS QPF. ETA MODEL SOUNDINGS INDICATING A
LITTLE CAPE (<100 J/KG). THERE IS A SLIGHT RISK OF THUNDER BUT NO
ENOUGH TO INCLUDE IN THE EXISTING FORECAST. NO LIGHTNING STRIKE
ANYWHERE THUS FAR. WILL CONTINUE TO OMIT.

NO CHANGES TO ANY OF THE LATER PERIODS.

.AVIATION...LOOK FOR IFR/LIFR CONDITIONS TO CONTINUE THROUGH TONIGHT
DUE TO LOW CEILINGS...BOUTS OF HEAVY RAIN AND EVEN SOME RAIN-INDUCED
FOG.

.HYDROLOGICAL DISCUSSION...FLOOD WATCH CONTINUES. DOPPLER RADAR
ESTIMATES INDICATE UP TO 4 INCHES HAVE ALREADY FALLEN IN SECTIONS OF
CENTRAL ULSTER COUNTY...WITH 1/2-2 INCHES ELSEWHERE IN OUR HSA. WE
HAVE ALREADY ISSUED A FFW FOR ULSTER COUNTY AND SOME MAIN STEM CREEK
FLOODING IS POSSIBLE IN THAT COUNTY. LOOK FOR AT LEAST ANOTHER 2
INCHES MORE TO FALL IN THE CATSKILLS...LOCALLY 3 MORE POSSIBLE.
ELSEWHERE 1/2-1 1/2 INCHES OF ADDITIONAL RAINFALL IS EXPECTED WITH
LOCALLY HEAVIER AMOUNTS. THE LIONSHARE OF THE HEAVIER RAIN FROM
ALBANY EASTWARD WILL BE CLOSER TO 00Z TUESDAY.

.ALY...FLOOD WATCH ALL ZONES THROUGH 400 AM TUESDAY.

HWJIV

***********PREVIOUS FORECAST DISCUSSION***************

...CORRECTED FOR ENDING TIME OF FLOOD WATCH...

DISCUSSION...
A MAJOR CIRCULATION CHANGE WILL OCCUR OVER THE NORTH AMERICAN
CONTINENT THIS WEEK.  COLD AIR WILL PLUNGE SOUTHWARD INTO THE
WESTERN UNITED STATES AS A MAJOR UPPER-LEVEL TROUGH FORMS THERE.
THE REACTION TO THIS WILL BE AN UPPER-LEVEL RIDGE SEA-SAWING
INTO THE EASTERN PART OF THE CONTINENT.  THUS, AS WE ENTER
THE MONTH OF NOVEMBER, WE WILL BE TRANSITIONING INTO A TYPICAL
NOVEMBER CIRCULATION PATTERN.

HOWEVER, BEFORE WE GET THERE, WELL HAVE TO DEAL WITH A WET SYSTEM
MOVING ACROSS THE COUNTY WARNING AREA TODAY AND TONIGHT.  AROUND
MIDNIGHT, THE WATER VAPOR IMAGERY WAS SUGGESTING THAT A VORTICITY
PACKAGE WAS DIVING INTO THE MID MISSISSIPPI RIVER BASIN.  THE
ANIMATION SUGGESTED THAT A DAMPENING WAVE WAS HEADING INTO EASTERN
CANADA WHILE A COUPLE OTHER WAVES WERE FROM IN THE VICINITY OF TEXAS
TO THE MID ATLANTIC REGION.  THE TEXAS WAVE WAS WELL-DEFINED IN THE
VAPOR PHOTOS, AND THE MID ATLANTIC FEATURE APPEARED TO BE IN THE
DEVELOPMENT STAGE, AND WAS LIKELY TIED THE THE VORTICITY PACKAGE IN
THE MIDWEST.

FOR SEVERAL DAYS, THE MODELS HAVE BEEN ADVERTISING THE DEVELOPMENT
OF A CYCLONE SOMEWHERE IN THE VICINITY OF SOUTHEASTERN NEW YORK
TODAY, AND THE LATEST MODEL ITERATIONS DONT INDICATE OTHERWISE.
THE MODELS CONTINUE TO FORECAST A SIGNIFICANT DUMP OF RAIN WITH THIS
FEATURE, AND THE TREND IN PREVIOUS RUNS WAS TO SHIFT IT A LITTLE
FURTHER EASTWARD.  THE LATEST RUN SUGGESTS THAT THIS TREND NO LONGER
CONTINUED, BUT FORECAST LOCATION HAS STABILIZED OVER THE PAST 24
HOURS.  CURRENTLY, RADAR COMPOSITES SHOW RAIN OCCURRING FROM MAINE
TO TEXAS.  IT IS MOST CONCENTRATED FROM THE OHIO VALLEY INTO
NORTHWESTERN NEW ENGLAND.  THROUGH THIS EVENING, THE AVIATION AND
NESTED GRID MODELS FORECAST THE RAIN TO BE HEAVIEST ALONG AN AXIS
FROM NORTHWESTERN VERMONT TO EASTERN PENNSYLVANIA.  THE ETA IS
FORECASTING A BROADER AREA OF HEAVY RAINFALL WHICH EXTENDS INTO
SOUTHWESTERN NEW ENGLAND.  THE CANADIAN REGIONAL MODEL FORECASTS THE
HEAVIEST RAIN FURTHER WEST THAN THE AFOREMENTIONED MODELS, AND
RELATIVE TO ITS FORECAST 24 HOURS AGO, ITS HEAVY RAINFALL AXIS
WAS FURTHER WEST.  IT HAS IT ALIGNED FROM NORTHERN NEW YORK INTO
CENTRAL PENNSYLVANIA.  THE NESTED GRID AND ETA MODELS HAVE SLIGHTLY
HEAVIER RAINFALL THAN THE AVIATION MODEL OR CANADIAN REGIONAL
MODELS, FROM 2 TO 2 AND A HALF INCHES IN A GOOD PORTION OF THE
COUNTY WARNING AREA.  FORTUNATELY, MOST MODEL FORECASTS HAVE THE
HEAVIEST RAINFALL TO THE EAST AND SOUTH OF THE AREA MOST PRONE TO
FLOODING IN ALBANYS COUNTY WARNING AREA (SOUTHWESTERN ADIRONDACKS).
THE RAINFALL VALUES FORECAST BY THE MODELS DONT REACH WHAT WOULD BE
REQUIRED TO CAUSE FLOODING ACCORDING TO THE FLOOD GUIDANCE, HOWEVER,
THERE IS ALWAYS THE PROBLEM OF LOCAL ENHANCEMENT, AND AT THIS TIME
OF THE YEAR, STORM DRAINS PLUGGED WITH LEAVES HAVE TO BE FACTORED
IN.  SINCE A FLOOD WATCH HAS ALREADY BEEN ISSUED FOR THE COUNTY
WARNING AREA, WELL RIDE WITH IT ON THE NEXT FORECAST ISSUANCE.
THE GUIDANCE MAXIMUM TEMPERATURES FROM THE THREE UNITED STATES
MODELS AGREE WELL WITH SUNDAYS ZONE FORECAST FOR TODAY.  THE
FORECAST PRESSURE GRADIENT IS RATHER SLACK TODAY, SO NO
SIGNIFICANT WIND IS EXPECTED.

RATHER STRONG DYNAMICS ARE FORECAST WITH THE DEVELOPING CYCLONE
THROUGH THIS EVENING.  THEY WANE AFTER MIDNIGHT, HOWEVER, AS THE
CYCLONIC SYSTEM WHIPS RAPIDLY NORTHWARD INTO CANADA.  THIS IS
REASONABLE AS THE UPPER-LEVEL CIRCULATION IS QUITE PROGRESSIVE WITH
A STRONG SHORT WAVE TROUGH FORECAST TO MOVE SOUTHEASTWARD FROM THE
CANADIAN PLAINS TO THE MIDWEST TODAY THROUGH TONIGHT.  THE MODELS
VARY SLIGHTLY AS TO THE POSITION OF THE SURFACE LOW PRESSURE LATER
TODAY, THE ETA IS SLIGHTLY RETARDED TO LOWER LATITUDES THAN THE
AVIATION, THE 2 CANADIAN MODELS, AND NESTED GRID.  MODEL CONSENSUS
IS THAT THE ETA IS TOO SLOW.  PERHAPS THIS SUGGESTS THAT THE
PRECIPITATION WONT BE QUITE AS HEAVY, LINGER AS LONG, OR BE AS FAR
SOUTHEAST AS THE ETA FORECAST SUGGESTS.  IN ANY CASE, THE LATEST
MODEL FORECASTS ALL SUPPORT THE IDEA OF SUNDAYS ZONE FORECAST THAT
THE RAIN WOULD BE TAPERING OFF AFTER THIS EVENING.  SO THE TIMING OF
THE CURRENT FLOOD WATCH, WHICH ENDS AT 4 AM TUESDAY, SEEMS
REASONABLE.  THE GUIDANCE PROBABILITY OF PRECIPITATION FROM THE
AVIATION AND NESTED GRID IS LOWER THAN THE ETA FOR TONIGHT, AS MIGHT
BE EXPECTED GIVEN THE SLOWER MOVEMENT FORECAST BY THE ETA.  THE
MINIMUM TEMPERATURES FORECAST BY MODEL GUIDANCE ARE QUITE SIMILAR
AND SUPPORT SUNDAYS ZONES.

LATEST MODEL FORECASTS INDICATE A WEAK RIDGE OF HIGH PRESSURE WILL
BUILD ACROSS EASTERN NEW YORK AND WESTERN NEW ENGLAND TUESDAY, AND
THAT IT WILL BE A DRY DAY.  GUIDANCE HIGH TEMPERATURES ARE SIMILAR
AND SUPPORT SUNDAYS ZONE FORECAST.  LITTLE, OR NO CHANGE TO THIS
PERIOD IS ANTICIPATED ON THE NEXT RELEASE OF THE ZONES.

THE LATEST MODEL GUIDANCE SUGGESTS THAT SOME SHOWERS MAY REACH THE
FORECAST AREA TUESDAY NIGHT.  THIS IS COVERED IN THE PREVIOUS ZONES,
AND LITTLE CHANGE IS LIKELY.  POSSIBLE REMNANT PRECIPITATION IS
FORECAST BY THE CANADIAN GLOBAL AND AVIATION MODELS FOR WEDNESDAY SO
THERES NO REASON TO CHANGE THE PREVIOUS ZONE FORECAST FOR THAT DAY.
THEN COMES A DRY PERIOD THAT LASTS INTO EARLY SATURDAY.  LATEST
GUIDANCE SUGGESTS THAT AN APPROACHING SEMI-BACKDOOR COLD FRONT COULD
TOUCH OFF SHOWERS LATE SATURDAY.  THIS FEATURE IS A BIT CLOSER TO
THE REGION ON THE CANADIAN GLOBAL THAN THE AVIATION.  THE EUROPEAN
MODEL SUGGESTS THAT IT MIGHT BE MORE OF A STATIONARY FRONT THAN A
COLD FRONT, SO THERES NO GOOD REASON TO CHANGE SUNDAYS ZONES,
WHICH HAD A DRY FORECAST UNTIL SUNDAY.

.HYDROLOGIC DISCUSSION...THE MODELS ARE INDICATING AT MOST 2 AND A
HALF INCHES OF RAINFALL FROM EARLY THIS MORNING INTO THIS EVENING.
THIS IS BELOW FLOOD GUIDANCE.  HOWEVER, THE POSSIBILITY OF TERRAIN
ENHANCEMENT, THOUGH NOT HIGHLY PROBABLE IN THIS SITUATION, SUGGESTS
LEAVING THE FLOOD WATCH IN EFFECT.  RAINFALL WILL TAPER OFF AFTER
THIS EVENING.  AFTER THAT, NO SIGNIFICANT RAINFALL IS EXPECTED INTO,
AND PROBABLY THROUGH THE WEEKEND.  RIVERS WILL BE ABLE TO RECOVER
FROM ANY HEAVY RAIN THAT OCCURS IN THE CURRENT STORM.

.AVIATION DISCUSSION...WIDESPREAD IFR CONDITIONS TONIGHT CONTINUING
THROUGH MONDAY.

.ALY...FLOOD WATCH ALL ZONES TODAY UNTIL 4 AM TUESDAY.

HEMMERICH

CTZ001-013-MAZ001-025-NYZ032-033-038>043-047>054-058>061-063>066-082>
084-VTZ013>015-272100-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE ALBANY NY
1005 AM EST MON OCT 27 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN NEW YORK AND ADJACENT
WESTERN NEW ENGLAND.

.DAY ONE...TODAY...FLOOD WATCH IN EFFECT TODAY AND TONIGHT.  2 TO 4
INCHES OF RAINFALL IS LIKELY OVER THE AREA...ESPECIALLY IN THE HIGHER
TERRAIN OF THE CATSKILLS...TACONICS...BERKSHIRES AND ADIRONDACKS.
RIVERS ARE RISING RAPIDLY...AND MAY EXCEED THEIR BANKS QUICKLY
DURING TODAY AND EARLY TONIGHT.

AT THIS TIME A FLOOD WARNING IS IN EFFECT FOR ULSTER COUNTY UNTIL 315
PM THIS AFTERNOON.

.DAYS TWO THOUGH SEVEN...NO HAZARDOUS WEATHER IS EXPECTED AT THIS
TIME.

.SPOTTER INFORMATION STATEMENT...PLEASE ACTIVATE SKYWARN
SPOTTERS...ESPECIALLY IN THE MOUNTAIN AREAS MENTIONED ABOVE.