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Area forecast discussion 
National Weather Service Upton New York 
739 am EDT sun Jul 6 2008 


Synopsis... 
an unsettled pattern will prevail through at least the first half 
of the week as tropical moisture interacts with weak disturbances 
along the western periphery of the Bermuda high. A diffuse frontal 
boundary currently just south of the region will lift north across 
the tri-state area tonight. Muggy conditions will prevail through 
middle-week with temperatures becoming hot by Tuesday. A cold front 
will approach middle-week and push off the coast by the end of the week. 


&& 


Near term /until 6 PM this evening/... 
a marine layer is currently in place across the region this 
morning...producing both low clouds and fog. This will be slow to 
burn off...especially at the coast. However...with convection 
upstream currently waning...debris aloft should decrease in 
coverage and thickness as the morning progresses. This should 
allow the marine layer to burn off...first inland and then 
eventually at the coast by late morning. Then...with at least 
partial sun...temperatures should have no problem rising into the 
lower 80s away from the coast. Models currently are slowing little 
to no instability for this afternoon. However...believe that a 
temperature/dew point profile of low 80s/low 70s this afternoon will 
produce some available energy. Will forecast a chance of showers 
and thunderstorms this afternoon with the peak of diurnal 
instability. Plenty of tropical moisture around...which will make 
any storms capable of producing localized heavy rain. 


&& 


Short term /6 PM this evening through Tuesday/... 
the frontal boundary will slide back north across the region 
tonight as the subtropical Atlantic ridge takes control and more 
substantial south to southwest flow develops. This will only work 
to transport higher moisture content air into the region. We will 
transition back to a more typical Summer pattern during the short 
term period with convection based more on diurnal instability. 
Best chances will come during the afternoon and evening periods 
with a lessor chance elsewhere. A weakening middle level shortwave 
upstream will slowly lift northeast as it dampens. However...given 
the steering flow aloft and increasing instability each day...will 
keep an ongoing pop while the tropical moisture is present. 


A deep-layered SW flow will transport warmer air up the eastern 
Seaboard...with 850 hpa temperatures rising a degree or two each 
day to 16 to 17 degrees c by Tuesday. As the low level flow turns 
more southwest on Monday and especially Tuesday...a decreasing 
marine influence will allow temperatures to climb to the middle 80s 
on Monday and around 90 on Tuesday away from the immediate south 
facing shores. 


Tropical moisture remains in place with precipitable water values 
generally between 1.5 and 1.75 inches through Tuesday. More 
favorable diurnal heating...Monday and especially Tuesday will 
lead to the threat of afternoon and evening convection. The 
vertical wind profile remains weak and unidirectional through the 
short term period...so organized convection is not expected. 
However...this could lead to slow moving cells. Flooding may 
become a concern as the week progresses. 


&& 


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 
dew points 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 /12z Sunday through Thursday/... 
light and variable flow becoming light east/southeast ahead of warm front. 
Winds turn S in wake of warm front this afternoon...increasing to 
7-12 knots. Light southerly flow tonight. 


Low clouds and fog will gradually mix out this morning with VFR 
conds expected by afternoon. May take until early afternoon across 
kgon. 


Scattered rain showers/thunderstorms and rain possible this morning as warm front works 
north. Then instability thunderstorms expected this afternoon. Best chance 
across kewr/kteb/kswf(sct to numerous)...with lower chances to 
the east. Sub-VFR ceilings/visibilities in heavy downpours and erratic winds 
(up to 25-30 kt) will be likely in any thunderstorms. 


Convection dies down between 00z and 03z...with low MVFR/IFR 
stratus/fog gradually re-developing after 02z and 06z. 


Outlook for 12z Monday through Wednesday...high pressure remains 
across the terminals into Wednesday. Monday through Wednesday will feature a 
chance of showers and thunderstorms as a surface trough develops during 
the day...and daytime heating increases instability. MVFR or lower 
conds in stratus/fog at night. 


&& 


Marine... 
a frontal boundary just south of the waters this morning...lifts 
north and washes out today. SW flow strengthens Monday through middle 
week between sub tropical high and low pressure system developing 
over the Great Lakes and tracking east-northeast. 


Wavewatch has seas on the ocean reaching Small Craft Advisory criteria by Monday 
morning. Have gone slightly slower than that (mon afternoon) as SW 
flow is only 10 to 15 knots tonight and then increasing to around 15 
knots on Monday. Winds Tuesday and Wednesday increase to 15 to 20 knots range ahead 
of complex low pressure. 


The persistent south to southwest flow will continue to dominate 
area waters through the period. Seas on the ocean should be above 
Small Craft Advisory level Tuesday through Thursday...slow to subside with SW swell having 
developed. 


&& 


Hydrology... 
scattered convection will continue into Wednesday with the potential for 
localized heavy downpours. The flood threat should be isolated 
early during this time period...but could become more of a 
concern by the middle of the week. 


&& 


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


&& 


$$ 
Synopsis... 
near term... 
short term... 
long term... 
aviation... 
marine... 
hydrology... 

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