Flash Flood Warning 3, NWS New York, NY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE UPTON NY
415 AM EDT TUE JUN 28 2005

.NEAR TERM (TUESDAY)...
UPPER RIDGING CONTINUES TO SLOWLY WEAKEN OVER THE EASTERN US WITH A
WEAK SHORTWAVE (ASSOCIATED WITH SUBTROPICAL WAVE) RIDING THROUGH THE
REGION FOR THE FIRST HALF OF TODAY. WHILE AT THE SURFACE...A
SUBTROPICAL WAVE CENTERED OVER CENTRAL NEW JERSEY WILL DRIFT NORTH
ACROSS THE REGION...AS HIGH PRESSURE TO THE NORTH AND EAST OF THE
AREA WEAKENS AND SLIDES OFFSHORE.

DENSITY OF FOG THIS MORNING HAS BEEN VERY VARIABLE. BANDS OF SHOWER
ACTIVITY MOVING THROUGH THE AREA APPEAR TO BE MIXING DOWN SOME DRIER
AIR FROM 600-850 HPA LEVEL IN THEIR WAKE. THEREFORE HAVE BEEN
RELUCTANT TO PUT UP A DENSE FOG ADVISORY AS NO ONE AREA HAS BEEN
UNDER A QUARTER MILE FOR AN EXTENDED PERIOD OF TIME.

MODELS CONTINUE TO HAVE A TOUGH TIME INITIALIZING THIS SUBTROPICAL
SYSTEM...UNDERDOING MOISTURE AND SURFACE FEATURES...BUT WILL USE
GENERAL SYNOPTIC SCENARIO AND CURRENT FEATURE PLACEMENT TO GUIDE
FORECAST.

THE SUB-TROPICAL LOW LOSES IT SURFACE SIGNATURE AND PULLS NORTH OF
THE REGION TODAY. RAIN ASSOCIATED WITH THIS SYSTEM SHOULD WORK NORTH
OF THE REGION BY MIDDAY WITH ACTUALLY SOME SUBSIDENCE BEHIND IT AS
SEEN ON WV IMAGERY. THIS SHOULD ALLOW FOR SOME BREAKS IN CLOUD-COVER
THIS AFTERNOON...ESPECIALLY INLAND. WITH DAYTIME HEATING...A
MOISTURE LADEN ATMOSPHERE...MESOSCALE BOUNDARIES FROM RAIN BANDS AND
DIFFERENTIAL HEATING...AND SYNOPTIC ASCENT FROM THE SLOW MOVING
SHORTWAVE/VORT ENERGY...SCATTERED CONVECTION SHOULD NOT BE HARD TO
SET OFF THROUGH THE DAY. BEST CHANCE FOR TSTMS WILL BE INLAND ALONG
TRACK OF VORT ENERGY AND WHERE LESSER MARINE INFLUENCE WILL ALLOW
FOR MARGINAL SURFACE STABILITY TO DEVELOP. WITH PWATS 1.75 TO 2
INCHES...LOCALLY TORRENTIAL DOWNPOURS SEEM TO BE MAJOR THREAT.

HAVE GONE A BIT ABOVE NORMAL FOR TEMPS INLAND TODAY WITH AFTERNOON
SUBSIDENCE BEHIND THE SUBTROPICAL WAVE AND THEREFORE BREAKS IN CLOUD
COVER...AND A S/SW FLOW. TEMPS ALONG THE COAST WILL RUN NEAR NORMAL
WITH SOUTHERLY FLOW OFF MID 60 DEGREE WATERS.
&&

.SHORT TERM (TONIGHT THRU WEDNESDAY NIGHT)...
HIGH AMPLITUDE RIDGE ALONG THE EASTERN SEABOARD CONTINUES TO BREAK
DOWN WITH AMPLIFYING UPPER TROUGH OVER OHIO VALLEY SLOWLY WORKING TO
THE EAST COAST. THE DEEP SW FLOW OVER THE REGION WILL KEEP A SUPPLY
OF TROPICAL MOISTURE IN THE REGION...WHILE WEAK SHORT WAVES/VORT
LOBES RIDING NE AHEAD OF THE TROUGH WILL PROVIDE SYNOPTIC ASCENT
OVER THE REGION.

WILL REDUCE POPS TO LOW CHANCE TONIGHT WITH LOSS OF DAYTIME HEATING.
WITH FLOW TURNING A BIT MORE SW TONIGHT WILL REDUCE STRATUS/FOG TO
NEAR COASTAL LOCATIONS FOR TONIGHT...PARTICULARLY EASTERN LI AND
CONN.

ON WEDNESDAY...THE COMBINATION OF SHORTWAVE ENERGY...DAYTIME
INSTABILITY...A MOISTURE-LOADED AIRMASS WITH PWS NEAR 2 INCHES...AND
LEE-SIDE TROUGHING WILL RESULT IN LIKELY/HIGH CHANCE POPS. THE EXACT
TIMING OF THESE SHORTWAVES IS DIFFICULT IN THIS FAST SW FLOW...BUT
BEST CHANCE FOR ACTIVITY WILL BE DURING THE AFTERNOON/EVENING HOURS
AND FROM THE CITY/INLAND WHEN AND WHERE THE BEST INSTABILITY WILL
EXIST.

BUFKIT SOUNDINGS INDICATE LONG NARROW CAPES WITH HIGH K
INDICES...INDICATIVE OF A TROPICAL AIRMASS. THUS THE MAJOR THREAT
WILL BE TORRENTIAL DOWNPOURS AND LOCALIZED FLOODING. AFTER
INTER-OFFICE COLLAB WILL ISSUE AN SPS TO HIGHLIGHT FLOODING
THREAT.

WITH ABUNDANCE OF CLOUD COVER WILL RUN MAX TEMPS ONLY SLIGHTLY ABOVE
NORMAL CITY/INLAND AND NEAR NORMAL COAST...DESPITE 850 HPA TEMPS
AROUND 16C AND SW FLOW. MIN TEMPS WILL RUN ABOVE NORMAL ALL AREAS
WITH DEWPOINTS HOLDING AROUND 70.

&&

.LONG TERM (THURSDAY THROUGH MONDAY)...
NO BIG CHANGES MADE HERE WITH CHANCES FOR SHOWERS AND TSTMS PRETTY
MUCH EVERY DAY UP TO AND INCLUDING FRIDAY AS RATHER TROPICAL AND
WEAKLY CAPPED AIRMASS PERSISTS. BOTH THE ECMWF AND GFSX BRING A COLD
FRONT THROUGH LATE FRI WITH A DRY...SEASONABLE HOLIDAY WEEKEND ON
TAP.
&&

.HYDROLOGY...
ANY SHOWERS AND TSTMS THAT DVLP OVER THE NEXT SEVERAL DAYS WILL BE
CAPABLE OF PRODUCING HEAVY DOWNPOURS AND A LOCALIZED
FLOODING THREAT.

MOST AREA RIVERS AND STREAMS WILL SEE AN OVERALL RISE IN WATER
LEVELS IN RESPONSE TO THE RAIN. AREAS THAT EXPERIENCE A THUNDERSTORM
COULD SEE A LOCALIZED SHARP RISE ASSOCIATED WITH THE HEAVIER RAIN.
&&

.AVIATION...
CIGS ACROSS THE AREA HAVE GENERALLY HELD AT IFR/LIFR OVER THE LAST
FEW HOURS. IT SEEMS THAT ONCE THE SHOWERS MOVE THROUGH...VSBYS
TEMPORARILY IMPROVE AND THEN COME BACK DOWN...BUT NOT AS LOW. THINK
THIS WILL PERSIST UNTIL THE SUN RISES. 00Z OKX SOUNDING SHOWS A DEEP
MOIST LAYER ALL THE WAY UP TO 925MB. LOW PRES OVER CENTRAL NJ IS
SLOWLY MOVING NORTHWARD AND ALTHOUGH CIGS MAY RISE TO MVFR...THINK
THEY WILL PREVAIL FOR MUCH OF THE DAY. MODELS ARE INDICATING SOME
BREAKS IN THE CLOUDS LATE IN THE AFTERNOON AND IF THIS HAPPENS THERE
IS A POSSIBILITY FOR TSTM DEVELOPMENT...MAINLY OVER INLAND AREAS.
FOG/STRATUS LOOKS TO RETURN AGAIN TONIGHT...BUT SWRLY FLOW WILL
LIKELY KEEP CONDITIONS BETTER THAN THEY WERE TONIGHT.
&&

.MARINE...
WILL KEEP HEADLINE FOR SCA FROM FIRE ISLAND INLET EASTWARD TONIGHT.
WINDS TURN MORE SOUTHWESTERLY TONIGHT AND THINK WE COULD REACH
MARGINAL SCA LEVELS FOR SEAS WITH THIS TRAJECTORY. WAVEWATCH
GUIDANCE HAS BEEN OVERDOING SEAS FOR THE LAST SEVERAL DAYS AND THINK
IT HAS AGAIN. BERMUDA HIGH REMAINS ANCHORED OFFSHORE WHILE GRADUALLY
BREAKING DOWN THROUGH THU. A WEAK WAVE OF LOW PRES WILL MOVE THROUGH
THE AREA WED NIGHT/THU...FOLLOWED BY A STRONG COLD FRONT FRI EVE.
&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NJ...NONE.
NY...NONE.
MARINE...NONE.
&&

PUBLIC: NV
MARINE/AVIATION: AL