textproduct: Binghamton

WHAT HAS CHANGED

A Flood Watch has been expanded to include all of Central NY and the Southern Tier through Wednesday evening. Otherwise, no significant changes were made to the forecast.

KEY MESSAGES

1) Thunderstorms and locally heavy rain will bring the potential for flash flooding and likely some minor river flooding through Wednesday and possibly into Thursday.

2) Above normal temperatures are expected through the entire week.

DISCUSSION

KEY MESSAGE 1...

A stationary front will remain parked over the region through at least Wednesday and possibly into Thursday. This will bring a long duration moderate to heavy rainfall to the region. Thus, a flood watch is now out for all of our NY Counties except Sullivan County at this time.

A very juicy atmosphere will remain in place for the next couple of days with PWATs running about 2 standard deviations above normal for this time of year. Also, strong mid level lapse rates are expected to increase over 7C/km by early this morning, however the lower levels will likely remain stable. Forecast model soundings are showing more instability than last nights runs, with potential for over 1000 J/kg west of the I81 corridor and about 300-500 J/kg across the eastern half of the region. Whether or not enough instability will build will be dependent on cloud cover this afternoon and the timing of when morning showers and thunderstorms dissipate. A long lull and more clearing in the clouds will be most likely across our western counties. The eastern half of the region should hold onto morning rain showers and clouds later into the morning and this would keep the environment more stable. Even so, a line of heavy showers and embedded thunderstorms this afternoon and tonight could still bring some gusty winds to the area. An isolated tornado cannot be ruled out due to the strong winds aloft.

The main concern with multiple rounds of showers and thunderstorms possible in the coming days will be the flooding and flash flooding potential.

Models show the front barely making it into southern PA or the northern Mid- Atlantic by Wednesday evening before it lifts back north a warm front on Thursday. This will bring another round of rain and showers to the area through Thursday night...with yet more rain potential on Friday as the center of the low and eventual cold front press through the area. The latest guidance continues to show the cold front stalling out as it approaches the Mid- Atlantic states due to a strong Bermuda High off the coast. This will open the door for a third system to bring more rain over the coming weekend. Behind this weekend system, a stronger front will should clear out the moisture for a while by the end of the weekend.

There are a lot of variables associated with each of these systems, however the simple fact that each system may stack more and more water across our increasingly sensitive watersheds lends careful watching.

KEY MESSAGE 2...

A nearly continuous warm, moist southerly flow will result in above normal temperatures for the entire week. Highs on Tuesday and Wednesday will likely be in the 60s to lower 70s. Somewhat "cooler" temperatures are expected on Wednesday and Thursday behind a shallow cold front, but temperatures will still be above normal (highs in the lower 50s to to upper 60s). A return to a warm, moist southerly flow will result in temperatures rising once again to the 60s and 70s for Friday and right through the weekend, but more rain is looking likely with a frontal system pushing through on Sunday.

AVIATION /12Z TUESDAY THROUGH SATURDAY/

An area of heavier showers and embedded thunderstorms, especially along the leading edge of the convection, is pushing south of SYR and RME and is expected to continue to press south and east toward the Southern Tier of NY through the rest of the morning. This morning convection is expected to weaken gradually as it moves southward but will lead to varying conditions from VFR to IFR at times, especially with regards to visibility.

A lull in the shower activity is expected early to mid afternoon before convection increases again later in the day and into the evening with an approaching cold front. Again there can be some embedded thunderstorms, especially after 20Z through about 04Z Wednesday. If there can be enough clearing this afternoon and instability, a few storms could be strong to severe, with the best chance being around ELM and ITH. Confidence in general is low though with regards to the timing of the evening storms and any severe potential given the clouds that are expected to be around for the first part of the day.

Outlook:

Wednesday through Thursday...a chance of rain showers and associated occasional restrictions possible. Thunder possible each afternoon.

Friday through Saturday...Scattered rain showers and low chance for afternoon thunderstorms; associated occasional restrictions possible.

BGM WATCHES/WARNINGS/ADVISORIES

PA...None. NY...Flood Watch through Wednesday evening for NYZ009-015>018- 022>025-036-037-044>046-055>057.