textproduct: Binghamton

WHAT HAS CHANGED

Rain has developed farther north than models suggested. Adjusted rainfall chances and QPF amounts this afternoon and evening portions of the Southern Tier into NEPA.

KEY MESSAGES

1) A low pressure system will bring cool temperatures and rain showers to the area this afternoon into the evening. Most of the rain will be south of the Mohawk Valley. High pressure builds in behind the system, bringing pleasant and dry conditions to the region on Friday

2) A deep upper level trough over the east coast this weekend will drive periods of showers across the area Saturday and Sunday, lingering into Monday. High pressure will move into the region through mid-week.

DISCUSSION

KEY MESSAGE 1...

A low pressure system currently centered over south central PA will be the main weather feature for the day. Rain has developed farther north than guidance has been suggesting over the past few runs. Rain amounts up to 0.25 inches can be expected over the Southern Tier with lighter rain amounts as you progress to the north. Only a trace is expected across the Wyoming Valley and to the north. The heaviest rain is near the center of the low, with divergence on the NW portion of the low driving some moderate rain showers. This will slowly track eastward as the afternoon progresses. Upper level dynamics look to increase as the afternoon progresses. By mid to late afternoon, a strengthening left entrance region of a jet streak is expected to be over the Catskills into Poconos. This will help deepen the surface low and bring periods of moderate rainfall over the Wyoming Valley into Pike county. Guidance is also suggesting that this upper level strengthening will shunt energy from the current low to a new and deeper surface low along the NJ coastline. This would reduce rainfall potential across the aforementioned areas during the late afternoon and evening hours. Currently, about 0.75- 1.10 inches are forecast to fall across the Wyoming Valley into Pike county this afternoon into the evening hours. Looking at flash flood chances, confidence in widespread flash flooding is very low. Flash flood guidance for NEPA is pretty high given the recent dry weather, with 1hr guidance hovering above 2 inches for most of the area. We are not expecting widespread convection so the chance for a period of 2+in/hr is very low. The track of the low should keep our region to the north of the warm sector and bring mostly stratiform rain. A deformation band could develop and bring an inch to portions of NEPA over a couple hour period, but rates are not expected to be high enough for flash flooding. Given the prolonged rain period, there could be ponding on roadways or some minor urban flooding across areas with poor drainage.

Rain is expected to exit the area by 9pm as the second low develops over NJ. High pressure will develop behind this departing system. The wet ground combined with light to calm winds and clearing skies will allow for widespread patchy fog with areas of dense fog, especially in the valleys. Fog should burn off by mid-morning with a pleasant Friday expected. Mostly sunny skies and NW flow will keep temperatures in the mid 70s to low 80s.

KEY MESSAGE 2...

The high pressure will not stick around for long as an upper level trough digging into the eastern US from Canada will be the next feature driving weather conditions this weekend.

The surface high over the area Friday will slide to the NE, but is expected to have a lobe extend back to the SW and remain over the CWA through Saturday morning. 925mb and 850mb heights also remain somewhat consistent through Saturday morning. These factors should help limit rainfall chances over the region. A surface low is expected to develop over the mid-atlantic and race north Saturday afternoon while another surface low develops over the eastern Great Lakes as the upper trough continues to amplify across the eastern US. Guidance remains somewhat unsure as to how these systems will develop and interact with the high pressure over NE New England continuing to exert its influence over the region through the day. It is trending toward the mid- atlantic low tracking to our east with light rain across the Poconos and Catskills, followed by more widespread rain showers across the area Sunday as the Great Lakes low slowly moves to the NE, west and north of the CWA. The upper trough is progged to begin to tilt negatively Sunday evening, helping to push the surface low out of the area to the NNE. Much of the rain should go with it, but a strong cutoff low at 500mb is forecast to dive into the area Sunday night thru Monday. This should allow for lingering showers on Monday mostly north of the Southern Tier. High pressure returns Tuesday into Thursday before the next weather maker moves into the region. Temperatures during this period should be average to slightly below average.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

The current rain showers moving through will mainly impact AVP this afternoon, which may result in MVFR, and potentially briefly lower, restrictions. Rain showers will also move through every other terminal except SYR/RME, but no restrictions, or very brief ones, are expected. Any remaining restrictions likely end in the evening, but IFR fog is expected to return again overnight for a few terminals.

Outlook...

Friday through Saturday morning...Mainly VFR conditions; areas of morning fog, especially near KELM.

Saturday afternoon through Sunday...Showers and potentially thunderstorms with associated restrictions.

Monday...Scattered showers at the Central NY terminals with associated restrictions possible.

Tuesday...Mainly VFR.

BGM WATCHES/WARNINGS/ADVISORIES

PA...None. NY...None.