990  
FXUS61 KOKX 040930  
AFDOKX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NEW YORK NY  
430 AM EST WED MAR 4 2015  
   
SYNOPSIS
 
 
DEEPENING LOW PRESSURE TRACKS ACROSS EASTERN CANADA TODAY WITH A  
COLD FRONTAL BOUNDARY APPROACHING AS A WAVE OF LOW PRESSURE  
DEVELOPS ALONG IT SOUTHWEST OF THE REGION. THE COLD FRONT SLIDES TO  
THE SOUTHEAST TONIGHT...WITH WAVES OF LOW PRESSURE TRACKING ALONG  
IT INTO THURSDAY. CANADIAN HIGH PRESSURE THEN BUILDS IN THROUGH  
THURSDAY NIGHT...THEN SLIDES TO OUR SOUTH THROUGH FRIDAY NIGHT. A  
SERIES OF WEAK COLD FRONTS CROSS THE REGION THIS WEEKEND INTO  
EARLY NEXT WEEK.  
 

 
   
NEAR TERM /UNTIL 6 PM THIS EVENING/
 
 
A WSW FLOW REMAINS ACROSS THE REGION THROUGH THE DAY TODAY. PRETTY  
MUCH A STEADY STATE ENVIRONMENT WITH TEMPS ONLY RISING A FEW  
DEGREES AND INTERMITTENT LIGHT RAIN.  
 
THE UPPER LEVEL JET STREAK OF AROUND 200 KT WILL BE APPROACHING  
THROUGH THE DAY. TEMPS REMAIN GENERALLY IN THE MID TO UPPER 30S TO  
KEEP PRECIPITATION IN THE FORM OF PLAIN RAIN. THE INTENSITY WILL  
BE RATHER LIGHT DUE TO THE AREA NOT BEING IN A FAVORABLE REGION OF  
LIFT RELATIVE TO THE JET STREAK PLACEMENT BUT INCREASED DIVERGENCE  
ALOFT SHOULD ALLOW FOR RAIN FIELD TO EXPAND.  
 
TEMPERATURES USED WERE A COMBINATION OF GMOS...NAM12 AND GFS40.  
 

 
   
SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/
 
 
MODELS IN GOOD AGREEMENT WITH NORTHERN STREAM ENERGY DIGGING DOWN  
THE FRONT RANGE OF THE ROCKIES INTO NORTHERN PLAINS/UPPER GREAT  
LAKES TODAY...INTERACTING WITH A SW US LOW...AND THEN GRADUALLY  
LIFTING ACROSS THE US TO EAST COAST BY THURSDAY NIGHT.  
 
HAVE STAYED CLOSE TO ENSEMBLE MEANS...WITH A REINFORCING COLD FRONT  
MOVING SOUTH OF THE REGION THIS EVE WITH FALLING TEMPS TONIGHT. A  
SERIES OF WAVES WILL DEVELOP ALONG A STATIONARY FRONT TO THE SOUTH    
..TRACKING NE THROUGH THE MID ATLANTIC
 
AHEAD OF APPROACHING UPPER  
TROUGH AXIS AND AS THE REGION FALLS UNDER FAVORABLE ENTRANCE REGION  
OF A 175-200KT UPPER JET.  
 
BIGGEST UNCERTAINTY EXISTS IN QPF...WITH MODELS WOBBLING BACK AND  
FORTH FROM RUN TO RUN ON NORTHERN EXTENT OF HEAVIER QPF AXIS.  
RELYING ON A ENSEMBLE APPROACH TO QPF...WITH 1/4 TO 3/4 INCH OF QPF  
ACROSS THE REGION AS THE SYNOPTIC SETUP TAPS INTO A MOIST SW FLOW  
ALL THE WAY FROM THE SUBTROPICAL PAC. ENSEMBLE INDICATING HIGHEST  
PROB OF .5 INCHES OR GREATER AFTER TRANSITION FOR SOUTHERN PORTIONS  
OF NYC/NJ METRO AND LI.  
 
MODELS IN GENERAL AGREEMENT WITH THERMAL PROFILES COOLING THROUGH  
THE OVERNIGHT...WITH A CHANGEOVER OF PRECIP FROM RAIN IN THE EARLY  
EVE TO WINTRY MIX THEN SNOW FROM NW TO SE. ALL AREAS APPEAR TO BE  
MAINLY SNOW BY 06Z. MODEST FRONTOGENETIC FORCING APPEARS TO BE ACROSS  
SOUTHERN ZONES...WITH POTETNIAL FOR SNOW TO BE HEAVY AT TIMES LATE  
TONIGHT THROUGH THU MORNING THERE...COUPLED WITH STRONG JET  
DYNAMICS. SNOW SHOULD GRADUALLY TAPER OFF IN INTENSITY AND COVERAGE  
FROM NW TO SE THURSDAY AFTERNOON AS SHORTWAVE TROUGH APPROACHES AND  
OFFSHORE STATIONARY FRONT SLIDES WELL OFFSHORE.  
 
HIGHEST CONFIDENCE IN 6+ INCH AMOUNTS IS FOR LI AND SOUTHERN  
PORTIONS OF NYC/NJ METRO. WILL UPGRADE TO WARNING IN THIS AREA AFTER  
COLLAB WITH PHI AND BOX. POTENTIAL FOR 3 TO 6 INCHES FOR COASTAL  
SOUTHERN CT...THE REST OF NE NJ...AND SOUTHERN PORTIONS OF LOWER  
HUDSON VALLEY. WILL LEAVE WATCH IN THESE AREAS WITH POTENTIAL FOR 6"  
BUT HIGHER LIKELIHOOD OF ADVISORY LEVEL. WITH A SHARP GRADIENT IN  
PRECIP ACROSS AREAS FAR N&W OF NYC...BETWEEN 1 TO 4 INCHES...  
NOT ENOUGH CONFIDENCE FOR AN ADVISORY AT THIS TIME.  
 
DRYING CONDITIONS THURSDAY NIGHT...WITH TEMPS DROPPING INTO THE  
SINGLE DIGITS...LOWER TEENS NYC METRO...ON GUSTY NW WINDS.  
WINDCHILLS LIKELY DROPPING TO AROUND ZERO TO 5 BELOW ZERO FOR MUCH  
OF THE REGION BY FRIDAY MORNING.  
 

 
   
LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/
 
 
THEREAFTER...MEAN TROUGHING CONTINUES INTO EARLY NEXT WEEK.  
UNSEASONABLY COLD CONDS (ABOUT 20 DEGREES BELOW SEASONABLE) CONTINUE  
THU NIGHT INTO FRI NIGHT AS CANADIAN HIGH PRESSURE BUILDS INTO THE  
REGION.  
 
THEN A SERIES OF WEAK SHORTWAVE/COLD FRONTS MOVE THROUGH THE  
REGION THIS WEEKEND INTO EARLY NEXT WEEK...WITH TEMPS MODERATING BUT  
STILL REMAINING SEVERAL DEGREES BELOW SEASONABLE. SOME LIGHT RA/SN  
SHOWER ACTIVITY POSSIBLE WITH ANY OF THESE DISTURBANCES.  
 

 
   
AVIATION /09Z WEDNESDAY THROUGH SUNDAY/
 
 
LOW PRESSURE TRACKS ACROSS EASTERN CANADA TODAY...WITH ITS TRAILING  
COLD FRONT CROSSING THE AREA LATE TONIGHT INTO THURSDAY MORNING.  
 
PCPN HAS ENDED FOR THE MOMENT AT ALL TERMINALS EXCEPT KGON...WHICH  
WILL FOLLOW SUIT OVER THE NEXT 1-2 HOURS AS WELL. HI RES MODELS ARE  
ALL OVER THE PLACE WITH TIMING PCPN TODAY...BUT EXPECTING AT LEAST  
2-3 HOURS OF DRY WEATHER. WATCHING NEXT AREA OVER CENTRAL  
PA...ALTHOUGH THE LEADING EDGE OF THIS HAS BEEN DRYING OUT AS IT  
ADVANCES EWD. THIS AREA IS CURRENTLY TIMED TO REACH WESTERN  
TERMINALS AROUND 10-11Z...BUT WILL NEED TO WATCH RADAR TRENDS TO SEE  
IF THIS WILL MATERIALIZE. ALL TERMINALS ARE NOW ABOVE THE FREEZING  
MARK...SO EXPECT PLAIN RAIN EVERYWHERE.  
 
ON AND OFF LIGHT RAIN IS THEN EXPECTED THROUGH THE DAY.  
 
IFR SHOULD PREVAIL THROUGH THE MORNING...ALTHOUGH CONDITIONS MAY  
BOUNCE AROUND TO LIFR AND MVFR AT TIMES. IFR OR MVFR LIKELY THROUGH  
THE REST OF THE DAY...ALTHOUGH STRATUS MAY SCATTER...ESPECIALLY  
ACROSS THE INTERIOR. IF THAT DOES OCCUR...VFR CONDITIONS ARE  
POSSIBLE FOR A TIME.  
 
SW WINDS 10 KTS OR LESS SHIFT TO THE SW-W. LLWS THROUGH 11Z OR SO.  
 
..NY METRO ENHANCED AVIATION WEATHER SUPPORT...  
 
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS  
CAN BE FOUND AT: HTTP://WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)  
 
KJFK FCSTER COMMENTS: EXACT TIMING OF RAIN THROUGH THE DAY IS  
UNCERTAIN. FLIGHT CATEGORY MAY VARY BETWEEN IFR AND MVFR THIS  
MORNING...AND MVFR AND VFR THIS AFTN.  
 
KLGA FCSTER COMMENTS: EXACT TIMING OF RAIN THROUGH THE DAY IS  
UNCERTAIN. FLIGHT CATEGORY MAY VARY BETWEEN IFR AND MVFR THIS  
MORNING...AND MVFR AND VFR THIS AFTN.  
 
KEWR FCSTER COMMENTS: EXACT TIMING OF RAIN THROUGH THE DAY IS  
UNCERTAIN. FLIGHT CATEGORY MAY VARY BETWEEN IFR AND MVFR THIS  
MORNING...AND MVFR AND VFR THIS AFTN.  
 
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS MODERATE...WHICH  
IMPLIES SLANT RANGE VISIBILITY 4-6SM OUTSIDE OF CLOUD.  
 
KTEB FCSTER COMMENTS: EXACT TIMING OF RAIN THROUGH THE DAY IS  
UNCERTAIN. FLIGHT CATEGORY MAY VARY BETWEEN IFR AND MVFR THIS  
MORNING...AND MVFR AND VFR THIS AFTN.  
 
KHPN FCSTER COMMENTS: EXACT TIMING OF RAIN THROUGH THE DAY IS  
UNCERTAIN. FLIGHT CATEGORY MAY VARY BETWEEN IFR AND MVFR THIS  
MORNING...AND MVFR AND VFR THIS AFTN.  
 
KISP FCSTER COMMENTS: EXACT TIMING OF RAIN THROUGH THE DAY IS  
UNCERTAIN. FLIGHT CATEGORY MAY VARY BETWEEN IFR AND MVFR THIS  
MORNING...AND MVFR AND VFR THIS AFTN.  
   
OUTLOOK FOR 06Z THURSDAY THROUGH SUNDAY
 
   
TONIGHT-THURSDAY
 
BECOMING IFR WITH A TRANSITION BACK TO SNOW  
AROUND MIDNIGHT. CHC N GUSTS TO 20 KT ON THURSDAY.   
THURSDAY NIGHT-FRIDAY
 
IMPROVING TO VFR THURS NIGHT. NW GUSTS  
15-20KT POSSIBLE THURSDAY NIGHT.   
SAT/SUN
 
VFR.  
 

 
   
MARINE
 
 
SCA CONDITIONS ARE EXPECTED TO CONTINUE ACROSS THE OCEAN WITH  
OTHER WATERS REMAINING BELOW SCA. THE SCA EVENT WILL BE MORE OF A  
MARGINAL ONE BUT ANY RAINFALL WILL BE HELP TRANSPORT MOMENTUM  
DOWN AND GIVE SOME HIGHER GUSTS THAT WOULD REACH SCA THRESHOLDS.  
WATER TEMPS ARE A FEW DEGREES WARMER ON THE OCEAN RELATIVE TO  
OTHER WATERS SO IT WILL BE RELATIVELY EASIER FOR HIGHER GUSTS TO  
BE ACHIEVED ON THE OCEAN.  
 
SMALL CRAFT ADVISORY CONDITIONS ARE LIKELY ON THE COASTAL OCEAN  
WATERS INTO THURSDAY MORNING AS A SERIES OF LOW PRESSURE WAVES  
TRACKS TO THE SOUTH OF THE WATERS. SOME UNCERTAINTY IF SCA CONDS  
CONTINUE INTO THU AFTERNOON...WITH HIGHER CONFIDENCE OF  
RE-OCCURRENCE THU NIGHT. SO FOR NOW HAVE ONLY RUN SCA UNTIL THU  
MORNING.  
 
SUB SCA CONDS RETURN FRI AS HIGH PRESSURE BUILDS OVER THE WATERS.  
 
A SERIES OF WEAK COLD FRONTS WILL MOVE THROUGH THE WATERS THIS  
WEEKEND INTO EARLY NEXT WEEK...ONE SATURDAY NIGHT INTO SUNDAY  
MORNING AND ANOTHER MONDAY NIGHT. WINDS APPROACH SCA CRITERIA  
SATURDAY INTO SATURDAY NIGHT AND THEN AGAIN MONDAY NIGHT INTO  
TUESDAY ON THE OCEAN WATERS...BUT AS OF RIGHT NOW...THEY SHOULD  
REMAIN BELOW. WAVES REMAIN BELOW SCA CRITERIA THROUGH THE PERIOD.  
 

 
   
HYDROLOGY
 
 
AROUND A QUARTER OF AN INCH OR LESS IS EXPECTED WITH THE REMAINING  
RAINFALL TODAY. LOW POTENTIAL FOR FLOODING ALTHOUGH SOME PONDING  
OF WATER IS EXPECTED WITH STEADY MODERATE RAIN THAT FALLS DUE TO  
EXCESS RUNOFF FROM MELTING SNOWPACK.  
 
1/4 TO 3/4 INCH LIQUID EQUIVALENT PRECIPITATION IS LIKELY WEDNESDAY  
NIGHT INTO THURSDAY. MOST OF THIS WILL BE FROZEN...SO HYDROLOGIC  
IMPACTS ARE NOT EXPECTED.  
 

 
   
OKX WATCHES/WARNINGS/ADVISORIES
 
 
CT...WINTER STORM WATCH FROM THIS EVENING THROUGH THURSDAY EVENING  
FOR CTZ008>012.  
NY...WINTER STORM WARNING FROM 7 PM THIS EVENING TO 7 PM EST  
THURSDAY FOR NYZ074-075-078>081-176>179.  
WINTER STORM WATCH FROM THIS EVENING THROUGH THURSDAY EVENING  
FOR NYZ071>073.  
NJ...WINTER STORM WARNING FROM 7 PM THIS EVENING TO 7 PM EST  
THURSDAY FOR NJZ107-108.  
WINTER STORM WATCH FROM THIS EVENING THROUGH THURSDAY EVENING  
FOR NJZ002-004-006-103>106.  
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EST THURSDAY FOR ANZ350-353-  
355.  
 

 
 

 
SYNOPSIS...JM/NV  
NEAR TERM...JM  
SHORT TERM...NV  
LONG TERM...NV  
AVIATION...24  
MARINE...JM/NV  
HYDROLOGY...JM/NV  
 
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