Preview of NWS' New Version of Forecast
This preview is not operational and should not be used for support decisions.

Area Forecast Discussion (AFD)

Issued by Binghamton, NY (BGM)

FXUS61 KBGM 201821

Area Forecast Discussion
National Weather Service Binghamton NY
221 PM EDT Fri Sep 20 2019

High pressure will bring fair weather and warm days to central 
NY and northeast PA through the weekend. Expect valley fog each
morning this weekend, then sunny or mostly sunny skies. A weak 
front will bring scattered showers and perhaps a stray thunderstorm
into the region on Monday. Mostly cloudy and cooler on Tuesday 
with isolated showers. Dry and seasonable mid week.


.NEAR TERM /THROUGH SATURDAY NIGHT/... Quiet, fair and warm 
weather will dominate the near term period as high pressure 
remains overhead. Only minor concerns will be for more valley 
fog (locally dense) late tonight into Saturday morning and cool 
overnight temperatures. Undercut NBM/Superblend guidance by a 
few degrees based on the past few nights and another efficient 
radiational cooling set up. Now have forecast lows in the 40s, 
except for some low 50s both in the Finger Lakes and in the 
Wyoming Valley region. Still may not be cool enough if skies 
remain clear and winds light.

Then, latest guidance is indicating just a bit of instability 
and moisture sneaking into Steuben County Saturday afternoon as 
a weak shortwave disturbance drops down from Ontario. Added in a
slight chance for a stray shower or storm to western Steuben 
County to account for this. Otherwise, dry and mostly sunny 
with highs well above average in the upper 70s to lower 80s.

Dry Saturday night and not as cool with a steady south wind
developing. Could still see some patchy valley fog, but the 
wind may allow for more mixing. Partly cloudy with lows in the 
50s east, and lower 60s west of I-81; a bit more humid.



A strong ridge of high pressure will still in place on Sunday. The 
high pressure system will temporally shift east in response to 
an approaching cold front from the Great Lakes. The main change
with the weather is that winds will become more southerly and 
southwesterly bringing in milder air. Given the recent dryness 
and what modeled 925 mb temperatures it could get quite warm on
Sunday with highs likely warmer than most of the statistical 
and blended data would indicate with highs in the 80's. 

The front will provide some lift but with very limited moisture.
It should be enough though for some showers to be around late 
Sunday night through Monday night. QPF continues to trend lower 
with this front as the modeling is keying more and more on the 
dry air in place that will take a while to moisten up. Modeled 
cape Monday afternoon and evening is still around 100 J/KG so a 
couple of rumbles of thunder can not be ruled out. Cloud cover 
will keep temperatures up in the 60's Sunday night and highs in
the 70's to around 80 on Monday. 

Behind the cold front, winds shift to the northwest. This will bring 
southward some moisture off the Great Lakes. Blended model data here 
appears too optimistic with the amount of clouds as this is usually 
a case where most of our region gets a cloudy day. A spotty shower 
or two in the Lake Effect regions is possible as well. Cooler 
air will advect in as well with temperatures back down into the
50's and 60's Monday night and Tuesday. 



Previous forecast discussion still on track.

Model solutions diverge towards the middle of the week, but 
they are hinting that another frontal system could affect the 
region by the end of the week, but major timing errors exist at 
this time. Would not be surprised if this next front gets 
delayed until Friday and that it will be a fairly dry front with
little rainfall, as it is going to be very difficult to break 
down the broad ridge that will be in place over the Eastern U.S.


VFR conditions with just a few high clouds and light winds
persist areawide into the evening hours.

Watching for fog to form once again at KELM, likely between
05-08z Saturday morning, becoming dense with visibilities 
perhaps under 1/2SM and CIGS down to just a few hundred ft agl 
between about 09-13z Saturday. Expect the fog to then rapidly 
break up, with vfr conditions returning here after 1330-1430Z 
Saturday. Confidence level moderate to high.

Other taf sites are expected to remain VFR through the period.

Outlook...Saturday afternoon through Sunday...VFR except late 
night/early morning valley fog expected for at least KELM; 
possibly KITH and KBGM for brief periods as well.

Sunday night through Tuesday...Mainly VFR, but some restrictions
possible in showers as front crosses, especially Monday 
afternoon and evening.

Wednesday...VFR conditions likely with high pressure building 
in. May see some patchy fog at KELM in the morning.