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Next 12 Hours

Forecast data from the National Digital Forecast Database.

5 Day Forecast

• Wednesday
• 
• High: 73 °
• Low: 52 °
• Chance of T-Storms

• Thursday
• 
• High: 66 °
• Low: 43 °
• Clear

• Friday
• 
• High: 66 °
• Low: 45 °
• Clear

• Saturday
• 
• High: 73 °
• Low: 45 °
• Partly Cloudy

• Sunday
• 
• High: 72 °
• Low: 54 °
• Chance of T-Storms

Area forecast discussion 
National Weather Service New York New York 
1015 am EDT Wednesday may 16 2012 


Synopsis... 
a low pressure trough will remain over the region this afternoon. 
A cold front will pass through tonight...followed by building 
high pressure from Thursday through the weekend. The high will 
then move east on Monday as a weak front approaches from the west 
on Tuesday. At the same time...weak low pressure along the middle 
Atlantic coast should stay just south of the region. 


&& 


Near term /until 6 PM this evening/... 
clouds will slowly give way to clearing through the day...then 
attention turns toward increasing instability and possible convection. 


By early afternoon...clearing will allow for destabilization and 
cape values to increase upwards of around 1000-1500 j/kg. Could 
see isolated storm develop over these western locations...close to 
pre frontal trough...differential heating. 


With a cold front approaching late in the day...could see some 
thunderstorms pop up primarily west of the Hudson. Bulk shear is 
forecast to be around 30kt with wet bulb zero heights 7-9kft and 
unidirectional flow. Biggest threats with any thunderstorms would 
be heavy rain and strong wind gusts...but large hail is also a 
threat considering the middle level lapse rates and cape in the -10c 
to -20c region. Storm Prediction Center carries a slight risk for severe T-storms 
just to the north of the Hudson Valley zones. 


Little change to temperatures...with trends depending greatly on where 
clearing occurs. Mav/NAM MOS blend looked good for highs...which 
will be above normal. 


&& 


Short term /6 PM this evening through 6 PM Thursday/... 
upper jet out ahead of the cold front that will pass through this 
evening may help sustain a line of showers and thunderstorms as they 
approach the northwest zones...but with the loss of cape...any storms 
probably weaken as they progress eastward through the County Warning Area. Have 
gone with slight chance to chance probability of precipitation for this threat. Again...some 
storms can be strong. 


Dry conditions and clearing skies overnight tonight into Thursday. 
Little in the way of moisture anywhere in the atmospheric column 
will result in a sunny day for Thursday. High temperatures will 
average a little above normal. Perhaps a late day sea breeze 
development occurring...but it probably will not affect the high 
temperature potential too much at the coastal areas. 


&& 


Long term /Thursday night through Tuesday/... 
global models are at odds with the 00z GFS and gefs early next week. 
Prior to that time though...large scale riding builds in both aloft 
and at the surface Fri-sun. Dry...mild conditions are forecast 
during this time frame. 


The differences arise from short wave energy left at the base of the 
departing East Coast upper trough early in the period. As the upper 
ridge builds over top of this feature...it eventually retrogrades or 
works west toward the middle Atlantic coast this weekend. The 00z European model (ecmwf) 
and ggem by early next week begin to lift the associated surface low 
north along the middle Atlantic coast toward the area with rain and 
easterly winds. The 84h hour NAM also points toward this evolution. 
Preference at this time is not to make wholesale changes and to see 
if the GFS comes into line with these solutions with subsequent 
runs. Thus...prefer to stay dry into early next week with some 
increase in cloud cover and rain chances Monday and Tuesday. This though 
is certainly something that could change based on the reasons just 
discussed. 


Highs during the period will generally be in the lower 70s at the 
coast...and middle to upper 70s NYC metropolitan and interior. Lows will be in 
the 50s. This is about 3 to 5 degrees above normal. Cooler temperatures are 
possible should the flow become more easterly over the weekend into 
early next weekend in response to low pressure tracking north along 
the middle Atlantic coast. 


&& 


Aviation /14z Wednesday through Sunday/... 
a surface trough will remain over the area today. A cold front will 
approach this evening and pass through tonight. 


Have just amended to indicate gradual improvement of current 
IFR/LIFR conditions through the morning...with VFR conditions 
expected at the NYC metropolitan terminals by 15z-16z...but holding on 
about an hour longer at kjfk/kisp/kbdr. Kgon looking more likely 
to remain IFR through the day and then return to LIFR at night. 


There is a brief window of opportunity for development of 
isolated/scattered showers/thunderstorms in vicinity of the surface trough just northwest of the NYC 
metropolitan terminals early this afternoon. Coverage and confidence are 
both too low at this time to mention in taf. 


Showers/thunderstorms with approaching cold front early this evening could 
make it to kswf and possibly khpn...but are unlikely to impact 
other terminals. 


Winds will remain around or just under 10 knots from the south 
today...with a cold front pushing through this evening and 
overnight...shifting winds to a northwest to north flow. 


..NY metropolitan enhanced aviation weather support... 


Detailed information...including hourly taf wind component forecasts can 
be found at: http:/www.Erh.NOAA.Gov/zny/n90 (lower case) 


Kewr fcster comments: amendments possible to fine tune timing of 
improving conditions. 


The afternoon ewr haze potential forecast is green...which implies 
slant range visibility 7sm or greater outside of cloud. 


Kjfk fcster comments: amendments possible to fine tune timing of 
improving conditions. 


Klga fcster comments: amendments possible to fine tune timing of 
improving conditions. 


Kteb fcster comments: amendments possible to fine tune timing of 
improving conditions. 


Khpn fcster comments: amendments possible to fine tune timing of 
improving conditions. 


Kisp fcster comments: amendments possible to fine tune timing of 
improving conditions. 


Outlook for 12z Thursday through Sunday... 
Thu-Sat...VFR. 
Sunday...areas of MVFR possible. 


&& 


Marine... 
dense fog has expired as visibilities slowly improve. Issued Small Craft Advisory for seas 
as latest observations do show an increase due to swell. 


Rest of the waters will remain below Small Craft Advisory criteria. Relatively 
tranquil conditions continue tonight into Thursday. 


High pressure builds over the waters starting Friday-sun with tranquil 
conditions. Winds will be generally 10 knots or less and seas 2-3 feet on 
the ocean and around a feet or less on Li sound/New York Harbor/Li bays. 


&& 


Hydrology... 
additional thunderstorms will be possible this afternoon into 
evening...but the coverage is not expected to be widespread. 
Still...urban/poor drainage is still possible in areas receiving 
locally heavier rainfall. 


There is the potential for rainfall Monday and Tuesday should low pressure 
along the middle Atlantic coast materialize and work northward. 
Preference at this time is for a dry forecast. 


&& 


Okx watches/warnings/advisories... 
CT...none. 
New York...none. 
New Jersey...none. 
Marine...Small Craft Advisory for hazardous seas until 6 PM EDT this 
evening for anz353-355. 
Small Craft Advisory for hazardous seas until 6 am EDT 
Thursday for anz350. 


&& 


$$ 
Synopsis...jc 
near term...jc/dw/pw 
short term...jc 
long term...dw 
aviation...Goodman/Sears 
marine...jc/dw/pw 
hydrology...jc/dw