999  
FXUS61 KOKX 180259  
AFDOKX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NEW YORK NY  
1059 PM EDT FRI APR 17 2015  
   
SYNOPSIS
 
 
A WEAK TROUGH OF LOW PRESSURE WILL MOVE THROUGH THIS EVENING. A  
COLD FRONT WILL APPROACH ON SATURDAY AND PASS THROUGH BY EVENING.  
HIGH PRESSURE BUILDS BRIEFLY ACROSS THE AREA ON SUNDAY AND THEN  
GIVES WAY TO AN APPROACHING FRONTAL SYSTEM FROM THE SOUTHWEST ON  
MONDAY. A FRONTAL WAVE PASSES JUST SOUTH AND EAST OF THE AREA MONDAY  
NIGHT...FOLLOWED BY A COLD FRONTAL PASSAGE TUESDAY MORNING. A SERIES  
OF WEAK COLD FRONTS OR TROUGHS WILL MOVE THROUGH DURING THE MIDWEEK  
PERIOD FOLLOWED BY HIGH PRESSURE AT THE END OF THE WEEK.  
 

 
   
NEAR TERM /UNTIL 6 AM SATURDAY MORNING/
 
 
AT 01Z...THE TROUGH OF LOW PRES WAS ABOUT HALFWAY THROUGH THE  
FORECAST AREA. IT WILL CONTINUE TO TRACK SE THROUGH THE REMAINDER  
OF THE EVENING...WITH ANY LINGERING SHOWERS COMING TO AN END.  
 
SKIES WILL CLEAR SKIES OVERNIGHT WITH A LIGHT NW FLOW. LOWERED  
LOWS A FEW DEGREES IN THE NORMALLY COOLER SPOTS DUE TO LIGHT  
WINDS AND CLEAR SKIES ALLOWING FOR GOOD RADIATIONAL COOLING  
CONDS...BUT STILL GENERALLY EXPECTED TO RANGE FROM THE MID 50S IN  
THE NYC METRO AREA TO UPPER 40S INLAND AND ACROSS EASTERN LONG  
ISLAND.  
 

 
   
SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/
 
 
SAT LOOKS TO BE THE WARMEST DAY OF THE YEAR THUS FAR...WITH  
MOSTLY SUNNY SKIES...DEEP MIXING WITH H8 TEMPS +8 TO +10C...AND  
DOWNSLOPE WESTERLY FLOW...LEADING TO HIGHS WELL INTO THE 70S EVEN  
ALONG THE COAST...AND UPPER 70S WEST OF NYC. GUSTY WINDS WILL  
LIKELY BEGIN BY LATE MORNING. A POTENT NRN STREAM SHORTWAVE DIVING  
ACROSS UPSTATE NY AND NEW ENGLAND IN THE AFTERNOON WILL DRIVE A  
COLD FRONT THROUGH DURING THE EVENING. THIS FRONT WILL BE  
ACCOMPANIED BY A BAND OF HIGH-BASED STRATOCU AND A NOTICEABLE  
INCREASE IN WIND...WITH GUSTS 25-35 MPH.  
 

 
   
LONG TERM /SUNDAY THROUGH FRIDAY/
 
 
RIDGING BOTH ALOFT AND AT THE SFC TRANSLATES WEST TO EAST ACROSS THE  
AREA ON SUN. TO THE WEST...AN AMPLIFYING FULL LATITUDE TROF WILL  
LIFT NORTH AND EAST ACROSS THE GREAT LAKES AND INTO THE NE MON INTO  
TUE. GLOBAL MODELS IN PARTICULAR...THE 12Z GFS AND ECMWF...ARE IN  
RELATIVELY GOOD AGREEMENT WITH SMALL TIMING DIFFERENCES...BUT LARGER  
DIFFERENCES EXIST WITH QPF.  
 
THIS WILL RESULT IN AN APPROACHING FRONTAL SYSTEM THAT WILL HAVE  
BOTH ATLANTIC AND GULF MOISTURE TO WORK WITH. PWAT VALUES WILL BE ON  
THE ORDER OF 2SD ABOVE NORMAL. A FRONTAL WAVE IS FORECAST TO PASS  
JUST SOUTH OF THE AREA MON NIGHT...IN ESSENCE KEEPING THE AREA JUST  
NORTH OF THE WARM FRONT. THE COLD FRONT FOLLOWS TUE MORNING. STRONG  
WAA ON MON WITH A 50-60 KT SE LLJ WILL PRODUCE MODERATE TO  
OCCASIONALLY HEAVY RAIN FOR MUCH OF THE DAY. INSTABILITY ALOFT COULD  
ALSO RESULT IN SOME ELEVATED THUNDER MON NIGHT. RAINFALL AMOUNTS OF  
1 TO 2 INCHES ARE FORECAST...WITH THE HIGHEST AMOUNTS FROM NYC AND  
POINTS NORTH AND WEST. THE SE FLOW WILL ENHANCE OROGRAPHIC LIFT.  
GUST UP TO 25 TO 30 MPH WILL POSSIBLE AT THE SFC ON MON...BUT TEMP  
PROFILES WILL BE INVERTED LIMITING ANY STRONGER WINDS FROM COMING  
DOWN.  
 
CONDITIONS DRY OUT TUE INTO WED WITH A SERIES OF WEAK FRONTS AND/OR  
TROUGHS MOVING ACROSS THE REGION. THESE WILL REINFORCE A SEASONABLE  
AIRMASS. HIGH PRESSURE THEN FOLLOWS FOR THE END OF THE WEEK. UPPER  
AIR PATTERN WILL BE DOMINATED BY A BROAD...FLAT TROUGH EAST OF THE  
MS RIVER VALLEY.  
 

 
   
AVIATION /03Z SATURDAY THROUGH WEDNESDAY/
 
 
A WEAK FRONT EXITS LI AND CT OVERNIGHT...ALLOWING HIGH PRES TO  
BUILD IN FROM THE W ON SAT.  
 
SOME PATCHY FOG HAS DEVELOPED AHEAD OF THE FRONT...IMPACTING KGON.  
THIS WILL DISSIPATE AFT THE FROPA. OTHERWISE...VFR THRU THE TAF  
PERIOD.  
 
WINDS SHIFT TO THE NW TONIGHT BEHIND THE FRONT...THEN BACK TO THE  
W OR SW SAT MORNING. WINDS WILL GUST 20-25 KT ON SAT...WITH HIGHER  
GUSTS POSSIBLE. SEA BREEZE DEVELOPMENT POSSIBLE ON SAT. BEST  
CHANCES FOR SEA BREEZES ARE WITH KJFK...KISP...AND KBDR.  
   
OUTLOOK FOR 00Z SUNDAY THROUGH WEDNESDAY
 
   
SAT NGT
 
VFR WITH DECREASING WINDS.   
SUN
 
VFR. SFC WND LIGHT NE BECOMING SE 10KT IN THE AFTN.   
MON
 
MVFR BECOMING IFR. INCREASING ESE SFC WND. G30-35KT IN AFTN.   
TUE
 
MVFR BECOMING VFR. G20-25KT.   
WED
 
VFR BECOMING SUB VFR BY THE AFTN.  
 

 
   
MARINE
 
 
S-SW FLOW 10-15 KT AHEAD OF AN APPROACHING WEAK COLD FRONT  
BUILDING OCEAN SEAS GENERALLY TO 3 TO 4 FT ON THE ERN OCEAN  
WATERS THIS AFTERNOON AND EVENING.  
 
NEAR SHORE SCA CONDS MAY BE POSSIBLE ON ALL WATERS SAT AFTERNOON  
AND EARLY EVENING WITH THE APPROACH AND PASSAGE OF A COLD FRONT.  
 
HIGH PRESSURE BUILDS EAST OF THE WATERS LATE SUN AFT WITH AN  
APPROACHING FRONTAL SYSTEM FROM THE WEST. THIS WILL RESULT IN A  
STRENGTHENING SE FLOW SUN NIGHT INTO MON WITH SCA CONDITIONS LIKELY  
ACROSS ALL WATERS. SEAS WILL BUILD TO 7 TO 10 FT ON MON...THEN WILL  
BE SLOW TO SUBSIDE MON NIGHT INTO TUE. SUB-SCA CONDITIONS ARE EXPECTED  
ACROSS THE REMAINING WATERS LATE MON NIGHT INTO WED.  
 

 
   
FIRE WEATHER
 
 
DRY WEATHER...MINIMUM RH 20-30 PERCENT...AND WINDS GUSTING TO  
25-35 MPH WILL LEAD TO ELEVATED POTENTIAL FOR FIRE GROWTH/SPREAD  
SAT AFTERNOON AND EARLY EVENING. SEVERAL WIND SHIFTS ARE EXPECTED  
THROUGH THE DAY...CREATING AN ADDITIONAL HAZARD WITH ANY ONGOING  
FIRES. INITIALLY NORTHWEST WINDS WILL SHIFT TO WEST- SOUTHWEST  
THEN SOUTHWEST THROUGH THE AFTERNOON...BEFORE RAPIDLY TURNING  
NORTHWEST AGAIN AROUND 6-7 PM WITH THE APPROACH/PASSAGE OF ANOTHER  
COLD FRONT. GUSTS MAY BRIEFLY STRENGTHEN AFTER THE COLD FRONTAL  
PASSAGE. A FIRE WEATHER WATCH IS IN EFFECT FROM 12 PM TO 8 PM  
GIVEN EXPECTED WEATHER CONDITIONS AND AFTER FEEDBACK FROM FIRE  
WEATHER OFFICIALS REPORTING DRY FUEL CONDITIONS.  
 

 
   
HYDROLOGY
 
 
THERE IS THE POTENTIAL FOR SIGNIFICANT RAINFALL WITH AN APPROACHING  
FRONTAL SYSTEM MONDAY INTO MONDAY NIGHT. STORM TOTAL RAINFALL WITH  
THIS SYSTEM WILL BE FROM 1 TO 2 INCHES...WITH THE HIGHEST AMOUNTS  
FROM NYC AND POINTS NORTH AND WEST. LOCALIZED HIGHER AMOUNTS WILL BE  
POSSIBLE IN THE HILLS NORTH AND WEST.  
 
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING  
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE  
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON  
OUR WEB SITE.  
   
COASTAL FLOODING
 
 
A PROLONGED PERIOD OF SE FLOW LATE SUN NIGHT INTO MON EVE WILL  
LIKELY RESULT IN WIDESPREAD MINOR COASTAL FLOODING. ASTRONOMICAL  
HIGH TIDES WILL BE RUNNING HIGH FOLLOWING A NEW MOON ON SAT. IN SOME  
CASES...DEPARTURES OF ONLY HALF A FOOT ABOVE NORMAL ARE NEEDED.  
STORM SURGE IS LIKELY TO PRODUCE WATERS LEVELS 1 TO 1 1/2 FT ABOVE  
NORMAL.  
 

 
   
EQUIPMENT
 
 
THE KOKX WSR-88D IS OUT OF SERVICE. TECHNICIANS ARE WORKING ON THE  
PROBLEM. ESTIMATED TIME OF REPAIR IS CURRENTLY UNKNOWN.  
 

 
   
OKX WATCHES/WARNINGS/ADVISORIES
 
 
CT...FIRE WEATHER WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY  
EVENING FOR CTZ005>012.  
NY...FIRE WEATHER WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY  
EVENING FOR NYZ067>075-078>081-176>179.  
NJ...FIRE WEATHER WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY  
EVENING FOR NJZ002-004-006-103>108.  
MARINE...NONE.  
 

 
 

 
SYNOPSIS...MD  
NEAR TERM...MD/24  
SHORT TERM...MD  
LONG TERM...DW  
AVIATION...JMC/JP  
MARINE...MD/DW  
FIRE WEATHER...  
HYDROLOGY...MD  
EQUIPMENT...  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab NY Page
The Nexlab NJ Page
The Nexlab CT Page Main Text Page