Weather

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fxus61 kokx 070858 cca 
afdokx 


Area forecast discussion...corrected 
National Weather Service Upton New York 
452 am EDT sun Sep 7 2008 


Synopsis... 
weak high pressure builds in from the west through tonight...then 
slides off the middle Atlantic coast on Monday and Monday night. A 
cold front will approach from the west on Tuesday...then cross the 
tri-state Tuesday night. High pressure then ridges in from the 
Great Lakes Wednesday and Wednesday night...then moves off the New 
England coast on Thursday. This high will then dominate our 
weather through Friday. A cold front will slowly approach from the 
west Friday night and Saturday. 


&& 


Near term /until 6 PM this evening/... 
winds should quickly diminish this morning (last lingering impact 
of hanna)...otherwise a typical early fall day (meteorological 
fall began September 1st). 20 knots of west-northwest downslope flow will minimize 
cloud cover and coupled with 850 temperatures of 13-15c will 
promote above normal temperatures today. Used a blend of 
mav/FWC/met temperatures...tempering mav numbers which have run a 
bit on the high side in similar regimes during the Summer. 


&& 


Short term /6 PM this evening through Tuesday night/... 
westward extension of Bermuda high builds in through the middle 
levels...with rising heights and zonal flow keeping things dry 
into Tuesday morning. Slightly cooler 850 temperatures will yield 
highs a bit cooler than today on Monday. Relatively clear sky 
conditions and light winds should promote decent radiational 
cooling tonight...with lows below normal (lower 50s normal cool 
spots middle 50s to around 60 elsewhere). Southerly return flow 
Monday night should result in lows a few degrees warmer Monday 
night than tonight. Followed a met/FWC blend at night (mav too 
warm) and a met/FWC/mav blend during the day (tempering mav 
numbers a tad but reflecting impact of downslope flow). 


An approaching strong cold front should bring a chance of showers 
and thunderstorms by Tuesday afternoon...with them becoming more 
widespread Tuesday night as the front crosses the tri-state. With 
1000-1500 j/kg of cape by late afternoon/early evening...Theta-E 
ridge building over area and decent shear...have the potential for 
some strong to possibly severe storms late Tuesday afternoon and 
evening. 


&& 


Long term /Wednesday through Saturday/... 
longer range models in fairly good agreement through Thursday 
night...then European model (ecmwf) is much faster in bringing a cold front through 
than the GFS to close the week (due to differences in handling 
high offshore). Due to these differences and no clear cut reason 
to favor one over the other...made little changes in the 
Friday/Saturday time frame (which already was leaning towards 
slower frontal passage. 


Will be noticeably cooler behind cold front Wednesday/Thursday with 
highs in the lower to middle 70s. Did lower lows Wednesday night (now 
have upper 40s in normal colder locations) and Thursday 
night...however believe that will end up being lowered further as 
guidance often underestimates amount of cold air behind these 
early season fronts (typically under does strength of high building 
in from south central canada)...then with high offshore and SW 
return flow setting up should see moderating temperatures 
Friday and Saturday. With differences in frontal timing do have 
chance probability of precipitation in Friday-Saturday (could end up being more diurnal 
Friday afternoon/evening and dry in the morning and late at night 
vice current blanket chance probability of precipitation currently in forecast). 


&& 


Aviation /08z Sunday through Thursday/... 
VFR condition in the wake of T.S. Hanna. 


Northwesterly wind gusts are problematic to NYC metropolitan 
configuration with ewr having more than 12 knots tail wind on runway 
11. 




Outlook for 06z Monday through Thursday... 
high pressure and VFR Monday. Showers/thunderstorms could produce sub VFR 
conditions Tuesday afternoon into Tuesday night ahead of an approaching 
cold front. High pressure and VFR conditions return Wednesday and Thursday. 


&& 


Marine... 
large sea/swell combination still exists in the wake of Hanna across 
ocean waters. This will produce pounding high surf and dangerous 
rip currents today...with the high surf diminishing today...but 
strong rip currents are expected to continue into Tuesday. Refer 
to the latest coastal flood statement for details. 


The pressure fields over the area supports a 
continuing decrease in winds speeds. However...seas will be a be 
slower to respond...mainly due to the longer period swell in place. 
A Small Craft Advisory currently in effect will expire for Li 
sound/New York Harbor/and all bays at 11am. Ocean waters will see small 
craft seas through tonight. 


High pressure building in will allow conditions to continue to 
diminish into Monday. 


Winds back to southerly and pick up again Tuesday ahead of a potent 
cold front. Small Craft Advisory winds may be reached south of Li ahead of the 
front...and gusty northwest winds and higher seas may necessitate a Small Craft Advisory on 
Wednesday morning. 


Long period swells from Hurricane Ike may impact the local waters 
through much of next week. 


&& 


Hydrology... 
there is the potential for around a half an inch of rainfall with 
locally higher amounts with showers/thunderstorms ahead of the 
cold front Tuesday afternoon and night. 


River flooding ongoing this morning. In New Jersey...The Saddle 
brook near Lodi remains above moderate flood stage...btu appear to 
be reaching its crest at this time near 7.8 feet. A river Flood 
Warning remains in effect through this morning until the flood stage 
of 6.0 feet is reached. 


Smaller streams in New Jersey have fallen below flood stage. 


The pomperaug river in New Haven County CT has gone above flood 
stage (9.0 feet)...but also appears to be cresting. No other new 
flooding is expected with rainfall having ended across the 
hydrologic service area...and river levels will continue to recede 
with dry weather Sunday and Monday. 


The next chance for rainfall is Tuesday afternoon and night...with 
about 0.5 inches expected basin wide. Locally higher amounts are 
possible in thunderstorms. 


&& 


Okx watches/warnings/advisories... 
CT...none. 
New York...high surf advisory until 6 PM EDT this afternoon for 
nyz075>077-080-081. 
New Jersey...none. 
Marine...Small Craft Advisory until 11 am EDT this morning for anz330- 
335-338-340-345-355. 
Small Craft Advisory until 1 am EDT Monday for anz350-353. 


&& 


$$ 


Public...maloit 
aviation...jst 
marine...bs 
hydrology...maloit/bs 

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