472 
fxus61 kokx 052049 
afdokx 


Area forecast discussion 
National Weather Service Upton New York 
449 PM EDT Sat Jul 5 2008 


Synopsis... 
an unsettled pattern will prevail through at least the first half 
of next week as tropical moisture interacts with weak disturbances 
along the western periphery of the Bermuda high. A diffuse frontal 
boundary just south of the tri-state area this evening will lift 
north Sunday evening. This will be the primary focus for showers 
and thunderstorms on sun. Warm and muggy conditions this weekend 
will be followed by hot weather for the middle of the week. 


&& 


Near term /until 6 am Sunday morning/... 
scattered convection continues to fire up this afternoon across 
interior New Jersey and the lower Hudson Valley where some sunshine has 
further destabilized the airmass. In addition...a shearing middle 
level vorticity will be skirting this area through early this evening. 
While instability is marginal...a deepening moisture profile and 
light steering will produce localized heavy rainfall through early 
this evening. 


The convection is expected to diminish this evening due to the 
loss of daytime heating...however...sct convection can not be 
ruled out with the close proximity of the shearing middle level 
short wave. 


It will be muggy with overnight lows around 70. 




&& 


Short term /6 am Sunday morning through Tuesday/... 
a sub-tropopause ridge parked offshore and a cutoff low over the Ohio 
Valley will aid the development of airmass thunderstorms sun and 
Monday. A diffuse frontal boundary just south of Long Island on sun 
will lift northward as the middle and upper flow backs around to the 
SW. This will result in high precipitable water air being drawn northward around 
the western periphery of the western Atlantic ridge...once again 
posing the threat for localized heavy rainfall. 


Surface warm front dissipates to the north Sun night as surface winds 
become SW. Plenty of cloud cover cover over the next couple of days 
will limit the heating potential. Highs on sun will top out in the 
upper 70s to lower 80s...then rise into the lower and middle 80s 
on Monday. A deep-layered SW flow will send 850 mb temperatures to 16c 
plus on Monday. There may be enough drying in the mixed layer on 
Monday with a SW flow for NYC and points north and west to become partly 
sunny. 


The filling upper low begins to shear out to the NE late Monday and 
Monday night with scattered convection firing up primarily in the after. Once 
again...there looks to be a heavy rainfall threat with precipitable waters  around 2 
inches. However...weak shear and moderate cape could provide a 
pulse severe event...especially for those locations that see sun. 


Scattered convection remains in the forecast on Tuesday as the weakening 
upper trough slides across the area. Partly sunny skies on Tuesday will 
send interior locations into the lower 90s...and the middle and 
upper 80s at the coast. Potential for pulse severe thunderstorms 
will increase with a high cape...weak shear environment. 


&& 


Long term /Tuesday night through Saturday/... 
high pressure over the Atlantic will continue to provide the region 
with a southerly flow. As a result...expect warm and humid 
conditions to continue across the tri-state area. Temperatures 
through the period will climb into the upper 80s to lower 90s with 
dewpoints in the 60s to near 70. Unsettled conditions will continue 
with the threat of showers and thunderstorms Tuesday night through 
Thursday.. the best chances for storms will be during the afternoon 
and evening hours. Drier weather is expected with slightly cooler 
conditions at the end of the long term period as high pressure 
builds in to the area. 


&& 


Aviation /20z Saturday through Thursday/... 
winds are consistent across the area with directions generally 
northeast to east and speeds under 8kts. The real challenge is 
ceilings/visible associated with abundant low moisture and scattered 
convection. Numerous sites have bounced from VFR to low end IFR 
within an hour. 


Expecting the coverage of thunderstorm to increase a bit through the 
afternoon as middle level clouds break up. Winds will be erratic 
in/near thunderstorms...but expect gusts to remain below 25-30kts. 


Winds continue to be light tonight. There may be issues with 
fog/low stratus after about 07z. NYC terminals should stay 
MVFR visible...but have IFR ceilings. 


Outlook for 18z Sunday through Wednesday...very unsettled weather 
pattern continues. Showers and thunderstorms trek from west to east 
through most of Sunday. As such...multiple chances for sub VFR 
ceilings and visibilities in showers and thunderstorms. Front 
likely moves north as a warm front sometime Sunday with VFR 
conditions. High pressure remains across the terminals into 
Wednesday. Monday through Wednesday there will be a chance of 
showers and thunderstorms as a surface trough develops during the 
day...and daytime heating increases instability. 


&& 


Marine... 
offshore ocean buoys (44025 and 44017) currently reporting seas 
around 2 feet. See no reason to deviate from the current state with 
a light east/southeast (5 to 10 kt) flow the next 24 hours. 


With a frontal boundary just south of the waters through 
Sunday...winds and seas will remain rather tranquil. The front 
then lifts north and washes out Sun night followed by a strengthening 
SW flow. Seas on the ocean are forecast to reach Small Craft Advisory criteria on 
Monday and remain there into Tuesday as SW winds increase to 15 to 20 knots. 


A persistent south to southwest flow will continue to dominate area 
waters through the period. Seas on the ocean will be at or above 
Small Craft Advisory level through Thursday...as a southerly swell develops. 


&& 


Hydrology... 
scattered convection will continue into Tuesday with the potential for 
localized heavy downpours. The flood threat should be isolated 
during this time period. 




&& 


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


&& 


$$ 
Synopsis...dw 
near term...dw 
short term...dw 
long term...British Columbia 
aviation...bs 
marine...BC/dw 
hydrology...dw 

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