-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KOKX 161804
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
204 PM EDT SUN JUN 16 2013

.SYNOPSIS...
A SERIES OF WEAK FRONTS WILL IMPACT THE AREA TODAY THROUGH
TUESDAY...WITH A COLD FRONT PUSHING EAST TUESDAY NIGHT. HIGH
PRESSURE RETURNS FOR THE REST OF THE WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SLIGHT ADJUSTMENTS TO THE FORECAST WITH THIS UPDATE BASED ON
LATEST TRENDS.

A SURFACE TROUGH WILL BE IN THE VICINITY THIS AFTERNOON. A CHANCE
FOR SHRA/TSRA EXISTS. THE OVERALL HIGHER PROBABILITY OF TSRA
APPEARS TO BE TO THE NORTH AND SOUTH OF THE REGION...WITH STRONGER
SYNOPTIC FORCING TO THE NORTH AND HIGHER INSTABILITY TO THE SOUTH.
THIS IS INDICATED IN EXPLICIT HIGH RES MODEL OUTPUT AS WELL.
LIMITED SUNSHINE AND WEAK MID-LEVEL LAPSE RATES WILL LIMIT
INSTABILITY OVER THE AREA TODAY...BUT WITH MODERATE DEEP LAYER
SHEAR...ANY ORGANIZING STRONG/MARGINALLY SEVERE TSRA ACTIVITY
ACROSS PA PRESENTS A SLIGHT THREAT FOR STRONG TO MARGINALLY SEVERE
STORMS INTO FAR W/NW/SW SECTIONS OF THE REGION LATE IN THE
AFTERNOON. ANY CONVECTION SHOULD WEAKEN AS IT TRACKS EASTWARD INTO
THE MARINE LAYER. STRONG WINDS AND HEAVY RAIN WOULD BE THE MAIN
THREAT WITH ANY ORGANIZED STRONGER CONVECTION.

THERE IS A MODERATE RISK OF RIP CURRENTS AT THE ATLANTIC OCEAN
BEACHES. BE AWARE...THE RIP CURRENT RISK COULD BECOME HIGH LATE
TODAY INTO THIS EVENING ACROSS THE NYC AND NASSAU COUNTY BEACHES
DUE TO A STRONG SEA BREEZE AND BUILDING SURF.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
ACTIVE ZONAL TO SLIGHTLY TROUGHED FLOW CONTINUES DURING THIS PERIOD
AROUND A PERSISTENT EASTERN CANADIAN UPPER LOW. THIS WILL BRING A
CONTINUATION OF WEAK WAVES/FRONTS AFFECTING THE REGION INTO TUESDAY.

OVERALL ONLY LOW TO MODERATE PREDICTABILITY IN SENSIBLE WEATHER
FOR MON AND TUE...AS EXACT TIMING OF SHORTWAVE ENERGY IS DIFFICULT
MORE THAN 24 HOURS OUT. SHORTWAVE AND FRONTAL TIMING WILL
DETERMINE COVERAGE OF SHRA/TSRA ACTIVITY EACH DAY.

ANY WEAKENING CONVECTION OR SHOWER ACTIVITY SHOULD CONTINUE TO PUSH
OFF TO THE EAST THIS EVENING. OTHERWISE...MILD CONDITIONS EXPECTED
WITH PATCHY FOG DEVELOPMENT POSSIBLE ALONG THE COAST ACROSS AREAS
THAT EXPERIENCE RAINFALL.

MONDAY AFTERNOON/EVE COULD PRESENT THE NEXT CHANCE FOR SHRA/TSRA
ACTIVITY. MEDIUM RANGE MODELS INDICATE BETTER INSTABILITY AND
SHEAR ON MONDAY...BUT THEY ALSO INDICATE THAT SURFACE TROUGHING
AND LOW- LEVEL JET WILL BE WEAKER ON MONDAY...AS WE WILL BE IN
BETWEEN RELATIVELY STRONGER FRONTAL BOUNDARIES DURING PEAK HEATING.
FOR NOW SO WILL KEEP CONVECTIVE CHANCE LOW AND MAINLY
INTERIOR...WITH BEST CHANCE IN VICINITY OF THERMAL TROUGHING. THIS
WILL HAVE TO BE RE-EVALUATED AS CONFIDENCE IN MODELS HANDLING OF
THIS IS LOW...BASED ON AFOREMENTIONED PREDICTABILITY ISSUES AND
LACK OF RUN TO RUN CONTINUITY.

MODELS COMING INTO SOMEWHAT BETTER AGREEMENT WITH EVOLUTION OF THE
MAIN SYNOPTIC FEATURES MON NIGHT/TUES...WITH A STRONG UPPER LOW
CURLING THROUGH ONTARIO/QUEBEC AND COLD FRONT APPROACHING THE REGION
MON NIGHT AND PUSHING THROUGH ON TUE. MAIN PREDICTABILITY ISSUE IS
THE TIMING OF SOUTHERN STREAM SHORTWAVES MOVING THROUGH IN THE
FLOW...WHICH WILL DETERMINE HOW WIDESPREAD SHOWER AND THUNDERSTORM
ACTIVITY WILL BE AHEAD/ALONG THE FRONTAL SYSTEM MON NIGHT/TUE. FOR
NOW WILL MAINTAIN CHANCE POPS. TOO MANY QUESTIONS TO GIVE ANY
DETAILS ON SEVERE WEATHER OR FLOODING THREAT.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
CONFIDENCE IS INCREASING IN DRY AND SEASONABLE CONDITIONS DURING
THIS PERIOD WITH NEAR ZONAL UPPER FLOW AND HIGH PRESSURE IN CONTROL.

NOT MUCH BEYOND PERHAPS A DIURNALLY INDUCED SHOWER OR
THUNDERSTORM THURSDAY THROUGH NEXT SATURDAY...MAINLY ACROSS
INTERIOR LOCATIONS.

TEMPERATURES WILL BE NEAR NORMAL.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
-- Changed Discussion --
A SURFACE TROUGH MOVES ACROSS THE REGION LATE THIS AFTERNOON INTO
EARLY THIS EVENING FROM WEST TO EAST. SCATTERED SHOWERS AND
POSSIBLY AN ISOLATED THUNDERSTORM WILL DEVELOP ALONG AND JUST
AHEAD OF THIS FEATURE...GENERALLY FROM 21Z TO 01Z. CONFIDENCE IS
MODERATE ON THE TIMING...BUT CHANCES OF CONVECTION ARE LOW AT ANY
ONE OF THE TERMINALS. THUS...HAVE KEPT THE MENTION OUT OF THE TAFS
AT THIS TIME. BRIEF SUB-VFR CONDITIONS AND GUSTS UP TO 30 KT ARE
POSSIBLE WITH ANY CONVECTION THAT DOES IMPACT A TERMINAL.

WINDS WILL BE S/SW THIS AFT AT 10 TO 15 KT WITH GUSTS UP TO 20
KT. LOW-LEVEL JET INCREASES TO 35 TO 40 KT BY 21Z...SO GUSTS UP TO
25 KT ARE NOT OUT OF THE QUESTION THIS AFTERNOON AWAY FROM THE
WATER WHERE THERE WILL BE A DEEPER MIXED LAYER. ALSO...A FEW
HIGHER SUSTAINED SPEEDS WILL BE POSSIBLE AT THE COASTAL TERMINALS.
WINDS VEER AROUND TO THE W THIS EVENING BEHIND THE TROF AT 5 TO 10
KT...THEN BACK TO W/SW ON MON AT AROUND 10 KT.

.OUTLOOK FOR 12Z MON THROUGH FRI...
.MON-TUE...SCT SHOWERS AND ISOLD-SCT TSTMS COULD BRING MVFR OR
LOWER CONDITIONS.
.WED-FRI...VFR.
-- End Changed Discussion --

&&

.MARINE...
SEAS EXPECTED TO BRIEFLY BUILD TO MARGINAL ADVISORY CONDS ON THE
OCEAN WATERS LATE THIS AFTERNOON/EVENING INTO TONIGHT ON STRENGTHENING
SOUTHERLY FLOW AHEAD OF A WEAK FRONT. HIGHEST PROBABILITY OF MARGINAL
SCA WIND/SEAS WILL BE ACROSS WESTERN OCEAN WATERS AND ENTRANCE OF
NY HARBOR WITH COASTAL JET FORMATION.

MARGINAL SCA SEAS ARE POSSIBLE INTO MON OR TUE...BUT LOOKING LESS
LIKELY WITH WEAK GRADIENT. A LIKELY RETURN TO SUB SCA CONDS FOR
MID THROUGH LATE WEEK AS HIGH PRESSURE BUILDS IN.

&&

.HYDROLOGY...
THE PROBABILITY FOR WIDESPREAD SIGNIFICANT RAINFALL IS LOW
THROUGH THIS WEEK. WITH RECENT HEAVY RAINFALL...ANY ORGANIZED
STRONG CONVECTION TODAY THROUGH TUESDAY WOULD PRESENT A LOCALIZED
THREAT FOR URBAN...POOR DRAINAGE AND SMALL STREAM FLASH FLOODING.

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
WEBSITE.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR ANZ350-353-355.
-- End Changed Discussion --

&&

$$