065 
fxus61 kokx 211900 
afdokx 


Area forecast discussion 
National Weather Service Upton New York 
300 PM EDT Thursday Aug 21 2008 


Synopsis... 
high pressure will remain over the region through Sunday. A cold 
front will approach Sunday night...and cross the area on Monday. 
High pressure then builds back in from the Great Lakes region and 
slides offshore by Thursday. 


&& 


Near term /tonight/... 
high pressure drifting farther out to sea will be absorbed by the 
Atlantic ridge tonight. Light to calm winds will allow for good 
radiational cooling away from the city. Lows will drop to around 50 
across the outlying suburbs and The Pine Barrens region of Long 
Island. Middle to upper 60s are expected in the city...with 50s to low 
60s elsewhere. 


&& 


Short term /Friday through Monday/... 
500 mb ridge will be over the northeast Friday morning...and flattens on 
Saturday. At the same time...high pressure at the surface remains 
strong enough to keep US dry. An onshore component to the winds will 
result in gradually increasing humidity levels through the weekend. 


Perhaps a few diurnal cumulus popping up on Friday along with 
over-the-ridge cirrus. So with still plenty of sun and mixing up to 
around 900-875 mb...highs are forecast to reach the middle 80s across 
the normally warmest spots away from sea breeze influences. FWC MOS 
numbers with a few adjustments were used in the grids. 


Saturday will probably feature some cirrus and more in the way 
diurnal cumulus vs Friday. With mixing up to 875-850 mb...think that 
highs will be similar to those on Friday...which turns out to be a 
degree or two higher than all MOS guidance for Saturday. 


On Sunday...500 mb trough will move across southern Canada...with an 
associated cold front moving through the Great Lakes. Models keep 
County Warning Area dry through 00z Monday...so will continue with a dry forecast 
for the daylight hours. In spite of more cloud cover...a SW flow 
should help temperatures away from the waters climb a couple of degrees 
warmer than on Friday and Saturday. 


Models are converging on a fairly slow frontal passage Monday 
afternoon...and clearing the entire County Warning Area sometime during the evening. 
Will go with chance probability of precipitation for showers/T-storms Sunday night (mainly 
after midnight) and Monday. 


&& 


Long term /Monday night through Thursday/... 
as a surface cold front departs Monday evening another ridge of high 
pressure builds into the area from the Great Lakes. Temperatures start 
near normal with winds out of the north then temperatures warm up 
each day through the end of the week as winds swing around to the 
east-southeast. 


&& 


Aviation /19z Thursday through Tuesday/... 
VFR conditions will prevail as high pressure centered over 
southern New England slides east of the area by this evening. 
Light sea breezes have made it through kjfk/kewr/kisp/khpn/kbdr/kgon 
as of 17z and are timed to move through klga and kteb around 1830z 
and 1930z respectively. Wind speeds are expected to remain around 
10 knots at NYC airports...less than 10 knots elsewhere. Light and 
variable winds tonight with land breezes possible...but not 
significant for tafs. Seabreeze/synoptic flow hybrid expected to 
develop between 14z and 17z again on Friday with speeds similar to 
those today. 


Outlook for 18z Friday through Tuesday... 
VFR should continue through at least Saturday as the high becomes 
nearly stationary east of Cape Cod through Saturday night. 
With a gradual increase in low level moisture and light winds at 
night...the potential for patchy fog and/or stratus will increase 
as well. Will need to monitor for sub-VFR conditions during the 
overnight hours this weekend. The chance for sub-VFR conditions 
will increase late Sunday into Monday as a cold front moves southeast 
toward the region. VFR expected on Tuesday as high pressure returns. 


&& 


Marine... 
no hazards expected in the short term. Seas on the ocean will build 
up to 4 feet on Sunday and Monday before a cold front passes through 
sometime on Monday or Monday evening with a chance of thunderstorms. 
Tranquil conditions prevail thereafter with high pressure building 
in behind the front. 


&& 


Hydrology... 
high pressure over the region will result in dry conditions through 
at least the daylight hours of Sunday. 


&& 


Okx watches/warnings/advisories... 
CT...none. 
New York...none. 
New Jersey...none. 
Marine...none. 


&& 


$$ 
Synopsis...jc 
near term...jc 
short term...jc 
long term... 
aviation...Alabama 
marine...jc/ 
hydrology...jc