000
FXUS61 KALY 080222
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
1020 PM EDT SUN SEP 7 2008
.SYNOPSIS...
A WEAKENING UPPER LEVEL DISTURBANCE WILL RACE ACROSS LAKE ONTARIO
INTO CANADA TONIGHT. SOME SHOWERS MAY IMPACT THE ADIRONDACKS AND
WESTERN PORTIONS OF THE MOHAWK VALLEY THIS EVENING. THEN A SMALL
AREA OF HIGH PRESSURE WILL KEEP OUR WEATHER TRANQUIL UNTIL A
STRONG COLD FRONT APPROACHES ON TUESDAY WITH A HIGH PROBABILITY
FOR SHOWERS AND THUNDERSTORMS.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
ONE MORE BATCH OF SHOWERS...ASSOCIATED WITH THE SHORT WAVE...WAS
MOVING INTO THE SOUTHERN ADIRONDACKS. THERE WERE A FEW LIGHTNING
STRIKES WHEN IT WAS OVER LAKE ONTARIO...BUT SBCAPES OFF MSAS WERE
NIL AND WE THINK THERE WOULD BE NO ADDITIONAL LIGHTNING STRIKES AS
THEY MOVE INTO THE REGION. ISSUED A NOWCAST SINCE THESE SHOWERS WILL
IMPACT ONLY A VERY SMALL AREA...WENT WITH A NOWCAST AND LET THE
GRIDS STAND.
THE REST OF THE AREA WILL REMAIN QUIET WITH PATCHY
CLOUDS...DIMINISHING OVERNIGHT. SOME PATCHY FOG MIGHT FORM BUT NOT
ENOUGH TO INCLUDE THE GRIDS. OVERNIGHT TEMPERATURES LOOK REASONABLE
AND WERE LEFT ALONE. UPDATED THE ACTUAL
HOURLIES/DEWPOINTS/AFM/PFM/FTP.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
A ZONAL FLOW REGIME UNFOLDS ACROSS THE NORTHEAST WITH A MIXTURE OF
SUNSHINE AND DIURNALLY DRIVEN AND ELEVATION CLOUDS. TEMPERATURES
WILL REBOUND AS FORECAST MIXING LEVELS AOA 850MB SUPPORT HIGHS M/U
70S FOR THE VALLEYS WITH M/U 60S FOR THE ELEVATIONS.
AN EVOLVING AND COMPLEX WAVE SEEN ACROSS MONTANA AND DAKOTAS WILL
BEGIN TO AMPLIFY THE FLOW ACROSS THE CENTER OF THE NATION MONDAY
NIGHT WITH HINTS OF AN UPPER LEVEL JET COUPLING TOWARD TUESDAY
MORNING. THIS WILL RESULT IN SURFACE PRESSURE FALLS ACROSS THE MID
WEST AND INCREASE LOW LEVEL WINDS /WARM SECTOR/ OVERNIGHT INTO
TUESDAY. TUESDAY CAN PROVE TO BE QUITE AN ACTIVE SEVERE WEATHER
DAY. AS NOTED IN THE PREVIOUS DISCUSSION...IMPRESSIVE WIND FIELD
AND MIXED LAYER CAPES AOB 1K J/KG ARE MORE THAN SUFFICIENT FOR
ORGANIZED CONVECTION. JUST HOW MUCH INSOLATION REMAINS TO BE SEEN
AS TRENDS FROM THE GLOBAL MODELS AND ENSEMBLE APPROACH SUGGEST
THIS FRONT MAY MOVE A FEW HOURS QUICKER AND MIGHT LIMIT SUNSHINE.
TAKE THAT IN ACCOUNT...WE COULD BE LOOKING A LOW CAPE HIGH SHEAR
ENVIRONMENT WITH 0-3KM HELICITIES IN EXCESS OF 200 M2/S2. IF SOME
CELLS WERE ABLE TO DEVELOP AHEAD OF THE MAIN COLD
FRONT...SUPERCELLS ARE A POSSIBILITY. ALONG THE FRONTAL
BOUNDARY...ORGANIZED LINE WITH EMBEDDED BOWS AS MID LEVEL JET OF
70+KTS PUNCHES INTO THE BACKSIDE OF THIS STRONG COLD FRONT. WILL
CONTINUE WITH LIKELY POPS AND BEGIN TO TIME FROPA A BIT FASTER
WHICH WILL REDUCE POPS QUICKLY FROM NORTHWEST TO SOUTHEAST TUESDAY
EVENING.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
SURFACE HIGH BUILDS IN FROM WEST FOR WEDNESDAY...WITH A COOL
CANADIAN AIR MASS. 850 HPA TEMPS PLUS 2 TO PLUS 5 ACROSS THE
REGION. GFS AND ECM IN FAIRLY GOOD AGREEMENT. WENT MOSTLY
WITH MEX GUIDANCE FOR HIGHS...NEAR 60 NORTH TO LOW 70S IN
HUDSON VALLEY...A FEW UPPER 50S ACROSS THE HIGHER ELEVATIONS
OF THE SOUTHERN GREEN MTNS OF VT.
LATEST GUIDANCE WAS SEVERAL DEGREES WARMER THAN THE PREVIOUS
RUN...BUT WILL STILL GET CHILLY WEDNESDAY NIGHT AND WITH HIGH
PRESSURE OVER THE REGION LOOKS LIKE FAVORABLE CONDITIONS FOR
RADIATIONAL COOLING. IT LOOKS ATTM THAT RISK OF FROST WILL
BE CONFINED TO THE NORTHERN HALF OF HAMILTON CO.
WINDS SWING AROUND TO THE SW THURSDAY AND TEMPS WILL CLIMB
INTO THE 60S WITH SOME LOW 70S IN WARMER LOCATIONS WITH
SUNNY SKIES.
ON THURSDAY NIGHT...THE FRONTAL SYSTEM THAT EXTENDS FROM
SOUTHERN CANADA INTO THE OHIO VALLEY APPROACHES THE REGION
FROM THE NORTHWEST...WHILE THE REMAINS OF IKE BRING A FLOW
OF WARM AND MOIST AIR INTO THE SOUTHERN STATES FROM THE
GULF. THIS WILL BRING ABOUT AN INCREASING AMOUNT OF
UNCERTAINTY INTO THE FORECAST FOR THE END OF THE WEEK...
AS THE TROPICAL SYSTEM INTERACTS WITH THE FRONTAL BOUNDARY
FARTHER NORTH. MODELS ARE NOT IN AGREEMENT AND THEREFORE
HAVE GONE TO LOW CHANCE POPS FOR FRIDAY THROUGH SATURDAY
AFTERNOON. FOR THE FORECAST TRACK AND INTENSITY OF IKE...
REFER TO THE PRODUCTS ISSUED BY THE NATIONAL HURRICANE
CENTER.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
SOME VFR CLOUDS WILL PASS BY DURING THE EVENING...ESPECIALLY NORTH
OF KALB WHERE THEY MIGHT BE A SPRINKLE BUT NOTHING THAT WOULD IMPACT
AVIATION OPERATIONS.
THE CLOUDS SHOULD HELP DELAY THE DEVELOPMENT OF RADIATIONAL
FOG...BUT IT LOOKS AS IF THEY WILL CLEAR OUT OVERNIGHT. AT THAT TIME
ANY BREEZE SHOULD BE GONE AND TEMPERATURES ARE PROJECTED TO DIP
BELOW THE CROSSOVER TEMPERATURE AT KGLF. THEREFORE WE ARE PROJECTING
IFR FOG FROM 08Z-12Z. ELSEWHERE WE ARE PROJECTING MVFR MIST AT KPOU
AND PERHAPS JUST ENOUGH OF BREEZE MIGHT MITIGATE THE FORMATION OF
FOG ALL TOGETHER AT KALB.
ANY FOG WILL DISSIPATE FAIRLY QUICKLY AFTER SUNRISE MONDAY LEAVING
US WITH VFR CONDITIONS AND INITIALLY A LIGHT S OR SW WIND BECOMING
MORE WESTERLY AND A LITTLE GUSTY...ESPECIALLY AT KALB...BY
AFTERNOON.
OUTLOOK...
MON NIGHT...VFR. NO SIG WX.
TUE...MVFR/CHC IFR...TSRA/SHRA LIKELY.
WED/THU...VFR. NO SIG WX.
FRI...VFR/MVFR...CHC OF SHRAS.
&&
.FIRE WEATHER...
GIVEN MOST OF THE REGION RECEIVED MODERATE TO HEAVY RAINFALL FROM
HANNA /EXCEPTION WOULD BE THE WESTERN MOHAWK VALLEY AND PORTIONS
OF THE DACKS/...FIRE WEATHER CONCERNS ARE RATHER LOW. KEETCH BYRAM
INDEX HAS DROPPED BELOW 300 FOR THE ENTIRE REGION. NEXT SHOT FOR
RAINFALL ARRIVES ON TUESDAY WITH A STRONG COLD TRACKING ACROSS THE
REGION.
THE WINDS WILL BE LIGHT FROM THE WEST OR SOUTHWEST AT 10 MPH
OR LESS TONIGHT. THE WINDS WILL BE FROM THE WEST SOUTHWEST ON
MONDAY AROUND 10 MPH.
RELATIVE HUMIDITIES TONIGHT RECOVER TO 85 TO 100 PERCENT BY MONDAY
MORNING...BUT LOWER TO 40 TO 55 PERCENT DURING THE AFTERNOON.
&&
.HYDROLOGY...
THE HOUSATONIC RIVER CAME UP 3 TO 4 FEET IN NORTHWESTERN
CONNECTICUT FROM THE RAIN FROM TROPICAL STORM HANNA. A GOOD
PORTION OF THIS RAIN SOAKED INTO THE GROUND. HEAVY RUNOFF
INTO THE POMPERAUG RIVER AND OTHER TRIBUTARIES DID BRING
THE HOUSATONIC ABOVE FLOOD BELOW THE STEVENSON DAM FOR A
FEW HOURS LAST NIGHT. IT HAS SINCE DROPPED THREE FEET PARTLY
DUE TO LAKE LILLINONAH BEING DRAWN PRIOR TO THE STORM. THE
HOUSATONIC WAS STILL RISING SUNDAY AFTERNOON...BUT IT IS
NEARLY 2 FEET BELOW FLOOD AND IS ONLY FORECAST TO RISE
ANOTHER INCH OR TWO. THE HOUSATONIC HAS LEVELED OFF AT
FALLS VILLAGE AND GREAT BARRINGTON UPSTREAM. THE STILL
RIVER BETWEEN DANBURY AND THE HOUSATONIC RIVER CAME UP
OVER 8 FEET FROM THE STORM BUT HAS DROPPED A FOOT SINCE
CRESTING EARLY THIS MORNING. IT WILL DROP BELOW FLOOD
AROUND MIDNIGHT TONIGHT.
THE NEXT PERIOD OF RAIN WILL COME TUESDAY AS A STRONG COLD FRONT
MOVES THROUGH. WIDESPREAD QPF AMOUNTS AROUND A HALF EXPECTED WITH
LOCALLY HIGHER AMOUNTS ASSOCIATED WITH THUNDERSTORMS. WITH THE
GROUND WET FROM THE RAINS ASSOCIATED WITH HANNA...THIS RAIN WILL
HAVE SOME EFFECT ON THE RIVERS ALTHOUGH AGAIN MOST OF IT WILL SOAK
INTO THE GROUND. A USGS OBSERVATION WELL NEAR PITTSFIELD HAS
INDICATED A RISE OF ABOUT 1.5 INCHES IN THE WATER TABLE THERE.
FOR DETAILS ON THE RIVERS...PLEASE VISIT THE ADVANCED HYDROLOGIC
PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...BGM
NEAR TERM...BGM
SHORT TERM...BGM
LONG TERM...RCK
AVIATION...FRUGIS
FIRE WEATHER...BGM
HYDROLOGY...RCK
FOR THE LATEST UPDATES...PLEASE VISIT OUR WEBPAGE AT
WWW.WEATHER.GOV/ALBANY
