855 
FXUS61 KBGM 241004
AFDBGM

Area Forecast Discussion
National Weather Service Binghamton NY
604 AM EDT Tue Jul 24 2018

.SYNOPSIS...
Wet and unsettled weather pattern will persist through Wednesday
night. Showers and thunderstorms with very heavy downpours are 
expected through the period with the activity most widespread 
during the daylight hours. Another period of showers and storms
Friday before a relatively quiet stretch this weekend with mild
temperatures.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
355 am update... 
Main concerns in the near term remain focused around the heavy rain 
showers and the potential for additional flash flooding across the 
southern tier of NY over to the Catskills and across all of ne PA.

A Flash Flood Watch remains in effect for the areas mentioned above 
as the supply of deep tropical moisture continues to stream 
northward through ern PA and central NY today through Wednesday. 

The area of attention this morning is the wrn half of Bradford 
county in PA and into Chemung county in NY where a line of heavy 
rain showers has set up through the overnight hours and over an inch 
of rain has fallen in the last 3 hours or so...with more rain 
upstream expected to track over the same area through at least this 
morning...possibly into the afternoon as well. This area has seen a 
good amt of rain the past several days, and soils are likely very 
saturated. So, any additional heavy rainfall rates will likely 
quickly become runoff and lead to flooding. A Flash Flood Warning is 
in effect for wrn Bradford county until 8:30 am this morning. 

Deep upper trough aligned from the Great Lakes south to around GA 
will continue to rotate multiple short waves northward on the east 
side of the trough which will continue to interact with the high PW 
air mass...around 1.75 to 2.25 inches...and produce N-S oriented 
heavy rain bands today through tomorrow. Should see some slight 
enhancement to the intensity during the afternoon and evening hours 
due to added instability from daytime heating. However, the 
potential for 1-2 inch per hour rainfall rates within the heaviest 
rain bands will likely be possible at any time. 

Will continue to monitor radar and satellite trends...along with the 
latest high resolution model guidance to get a better handle on 
where the heaviest rain will set up. Where these heavy bands do 
develop...if they track over the same areas, or across sensitive 
areas that have pre-conditioned saturated soils, then more flash 
flooding will likely become a concern.

The axis of highest PWAT air will begin to shift to the east on 
Wednesday, but as this occurs the main upper trough will also shift 
east and act to provide the necessary lift, that should produce
additional showers and thunderstorms through the day. The 
forcing may actual lead to more efficient rain producers...which
would increase the threat for flash flooding even more, 
especially in sensitive areas. 

At this time the threat for main stem river flooding still appears 
to be minimal at best, with a few forecast points along the 
Susquehanna and the West Branch of the Delaware River approaching 
action stage with the latest river forecast.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
An Atlantic-based high pressure system will continue to spin
over ocean waters while a trough digs down through Ontario
Province. These two systems will keep a persistent southerly
flow over NY and PA, importing warm, humid air, indicated by
PWAT values in the 1.50 to 2.00 inch range.

A series of short waves moving through the flow will provide the
impetus for showers and thunderstorms through the short term
period. The best chance for rain will come Wednesday night, when
a slow moving frontal system spins out of the Mid-Atlantic and
into Eastern New York.

Another front is forecast pull through our region late-Friday.

&&

.LONG TERM /SATURDAY THROUGH MONDAY/...
405 AM update...

Not much change to the latest model runs. Made minor 
temperature and POP changes to the long term forecast.

Previous discussion...

Saturday through Sunday night: 

High pressure will move into the area this weekend allowing for some 
potential drier windows. However, modeling shows another mid-level 
shortwave which could spark off isolated showers or storms Saturday 
afternoon and evening, slight chance pops for now. Overnight lows 
should cool into 50's and low 60's with highs in the 70's to low 
80's. 

Monday: Another system will head northeast from the Ohio Valley into 
our region. Overrunning showers would occur Monday with the current 
modeled setup with additional rounds of showers and thunderstorms 
just beyond the extended period. Heavy rainfall would be a threat 
but with this still many days away model data will likely change 
some as we draw closer to early next week. Continued temperatures in 
the 60's and 70's.

&&

.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
A persistent flow of moisture will keep showers and mainly MVFR
conditions over the terminals through early Wednesday. 

Brief periods of heavy showers on Tuesday will further degrade 
conditions, bringing temporary IFR visibilities and ceilings to 
our terminal sites.

Winds will be from the south at 8 to 12 knots with gusts of 15
to 20 knots through the afternoon.

Outlook... 

Wednesday through Thursday...Occasional restrictions likely, 
with periods of showers and thunderstorms.

Thursday night/Friday...Brief restrictions possible in 
scattered showers and thunderstorms.

Saturday...Mainly VFR.

&&

.BGM WATCHES/WARNINGS/ADVISORIES...
PA...Flash Flood Watch through Wednesday evening for PAZ038>040-043-
     044-047-048-072.
NY...Flash Flood Watch through Wednesday evening for NYZ022>025-
     044>046-055>057-062.

&&

$$
SYNOPSIS...BJT
NEAR TERM...BJT
SHORT TERM...DJP
LONG TERM...DJP/MWG
AVIATION...DJP