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Next 12 Hours

Forecast data from the National Digital Forecast Database.

5 Day Forecast

• Friday
• 
• High: 70 °
• Low: 46 °
• T-Storms

• Saturday
• 
• High: 59 °
• Low: 41 °
• Rain

• Sunday
• 
• High: 70 °
• Low: 43 °
• Chance of Rain

• Monday
• 
• High: 73 °
• Low: 43 °
• Clear

• Tuesday
• 
• High: 75 °
• Low: 54 °
• Partly Cloudy

Area forecast discussion 
National Weather Service New York New York 
519 PM EDT Friday may 24 2013 


Synopsis... 
cold front moving east of the region early this evening will have 
a low develop along it. The low deepens along the front into the 
Gulf of Maine on Saturday and weakens Saturday night. Low pressure 
lifts to the Canadian Maritimes early in the week as high pressure 
builds. A warm front will approach by middle week...moving briefly to 
the north...then dropping back to the south by late week. 


&& 


Near term /until 6 am Saturday morning/... 
upper level trough closes off into the region tonight with surface 
cold front pushing farther east of the region. A low develops along 
the front. Cold air advection will continue behind the front with 
higher positive vorticity advection aloft keeping showers from time to time tonight. The 
boundary layer winds increase and keep more mixing conditions in 
place. A slightly lower than mav/met blend was used for lows which 
will be in the upper 40s. 


There will be a high risk of rip currents into early this evening 
along the Atlantic facing beaches of Long Island. 


&& 


Short term /6 am Saturday morning through Saturday night/... 
the upper level low moves across and east of the region on Saturday 
while deepening with a dip in the jet stream moving across our 
region. A much cooler than normal day is in store along with 
showers developing again with the diurnal instability and cold pool 
aloft. Surface low develops starts to deepen in the Gulf of Maine. 
Low level jet of around 40-50 knots develops near 925 mb and with 
expectation of good mixing the maximum gust potential could reach 40-45 
knots. This is most pronounced with the GFS BUFKIT soundings with NAM 
BUFKIT keeping it more in the 35-40 knots range. Increased wind gusts a 
good 10 knots above previous forecast package and is a few kts below 
criteria but there is a chance that some sites could see gusts in 
the 40-45 knots range Saturday...probably middle to late afternoon into 
early evening. Also of note is the cold pool aloft and weak 
instability shown by MUCAPE of almost 100 j/kg. Therefore...isolated 
thunderstorms cannot be ruled out and with the much colder temperatures 
aloft...hence some showers or thunderstorms could produce small 
hail. 


A mav/met/nam12 blend used for highs but adjusted downward with 
highs mostly in the upper 50s to near 60 in urban northeast New 
Jersey. 


For Saturday night...advections decrease in efficiency with upper 
level low stacking and surface low in Gulf of Maine halting in 
further deepening...losing structure. Winds will begin to lighten. 
Drier conditions will begin to materialize with probability of precipitation gradually 
lowering through the night. Colder night than Friday night with 
mav/met blend used once again. Lows forecast into the low to middle 
40s. 


&& 


Long term /Sunday through Friday/... 
models in general agreement into early next week as upper closed low 
opens...eventually lifting to the northeast. High pressure ridge 
builds...with it/S axis remaining to the west through much of the 
week. 


At the surface...low pressure departs as high pressure builds. A warm 
front then approaches Tuesday from the west or southwest. 


By middle week...there are differences on handling of surface features with 
subtle differences noted aloft. Will follow wpc with the forecast at 
this time...which leans toward European model (ecmwf). It does appear that showers 
and possible thunderstorms could ride along the front...in the northwest 
to southeast upper flow as the axis remains to our west. However...not too 
sure how far north any of this activity will propagate...but will 
need to introduce probability of precipitation late Tuesday through Tuesday night. 


Weak low on the front moves east Wednesday as the front lifts to the 
north. Vorticity advection rides along the northwest/southeast upper flow...with 
potential higher coverage for showers/thunderstorms mainly to the north 
Thursday. Low pressure riding along the front moves east by 
Friday...allowing the front to drop south across the area. As 
such...at least minimal probability of precipitation warranted Wednesday...with slight 
chance at best Thursday and Friday. 


Temperatures still run below normal Sunday as cold pool slowly loses it/S 
grip across the northeast. Then near normal temperatures of 50s at night 
and 70s during the day will slowly warm up by late week as ridge 
axis makes eastward progress. Temperatures about 5 degrees above 
normal...or around 80 to the Lower/Middle 80s away from the south facing 
shores looks reasonable per wpc/ec MOS late week. 


&& 


Aviation /21z Friday through Wednesday/... 
low pressure near Cape Cod will deepen over the Gulf of ME tonight and 
Sat. 


Northwest winds through the remainder of the afternoon with sustained around 20 knots. 
Rain continues to expand northward up the New Jersey coast into the Hudson 
Valley...so the city terminals will receive a steady -ra into the 
evening. Winds will likely drop a little as the rain tracks through the 
area. 


Sustained winds near 20 knots tonight...with potential gusts to 30. Gusts 
may only be occasional however so slightly lower speeds indicated in tafs. 
MVFR continues with -ra. 


Sustained northwest winds near 25 knots Sat. Peak gusts may exceed 35 knots. Ceilings 
expected to slowly lift above MVFR levels. 


There is the potential for gs in rain showers Sat with cold temperatures aloft. 
Although tops will be blw 20k feet...isolated lightning possible. 




New York 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: -ra may persist until 23-00z. 


Kjfk fcster comments: visibility may be closer to 5-6sm if steadiest -ra 
remains west of the Airport. -Ra may persist until 23-00z. 


Klga fcster comments: visibility may be closer to 5-6sm if steadiest -ra 
remains west of the Airport. -Ra may persist until 23-00z. 


Kteb fcster comments: -ra may persist until 00z. 


Khpn fcster comments: occasional IFR ceilings possible through 00z. Visibility may be 
closer to 5-6sm if steadiest -ra remains west of the Airport. -Ra may 
persist until 00z. 


Kisp fcster comments: conditions may drop blw forecast levels if -ra 
field expands further east than expected. 


Outlook for 18z Saturday through Tuesday... 
Sat afternoon...mainly VFR with areas of MVFR. Showers. Northwest gusts 
around 35 knots. 
Sun...VFR. Chance showers mainly in the morning. Northwest gusts 30-35kt. Forecast 
may change if departure of storm slows. 
Monday...VFR. 
Tue-Wed...MVFR or lower possible in vicinity of a warm front. 


&& 


Marine... 
fog should be breaking up with visibility improvement as winds become gusty 
from the northwest. Next issue is winds...small craft tonight and 
gales on Saturday in response to low deepening in the Gulf of 
Maine. The winds begin to subside late Saturday night as that low 
weakens. Seas on the ocean remain elevated in the 5-8 feet range 
for the short term through Saturday night. 


Low pressure passes well to the northeast Sunday and Monday as high 
pressure builds. Gusty northwest flow backs in time to the west or southwest 
as speeds diminish. A warm front approaches the waters Tuesday and Wednesday 
with south to east winds prevailing this time frame. 


Rough ocean seas per wave watch iii early Sunday will subside as the 
storm departs. 


&& 


Hydrology... 
additional rainfall will be around 0.25 to 0.5 inch with locally 
higher amounts possible through Saturday night. No flooding 
problems are anticipated. 


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... 
CT...none. 
New York...none. 
New Jersey...none. 
Marine...Small Craft Advisory until 6 am EDT Saturday for anz330-335- 
338-340-345-350-353-355. 
Gale Warning from 6 am Saturday to 6 am EDT Sunday for anz330- 
335-338-340-345-350-353-355. 


&& 


$$ 
Synopsis...jm/pw 
near term...jm 
short term...jm 
long term...precipitable water 
aviation...jmc 
marine...jm/pw 
hydrology...jm/pw