textproduct: Binghamton

WHAT HAS CHANGED

Little change from previous forecast.

KEY MESSAGES

1) Active and warm weather pattern for the coming week as southwest flow steers moisture and shortwaves into our area, bringing rain and thunderstorm chances for much of the week.

2) Threat for severe thunderstorms Tuesday and Wednesday, with isolated hail and strong wind gusts possible with stronger storms.

DISCUSSION

KEY MESSAGE 1...

A strong ridge is developing across the SE US with NY and PA being on the northern fringe of the high pressure. With the center of the high pressure along and just off the SE US coast, moist flow up into our region out of the Gulf will keep us warm. Being on the north side of the ridge also means that we will be in an active "ring of fire" pattern with frequent 500 mb shortwaves passing through, leading to chances of showers and thunderstorms for portions of the region every day. With a long wave trough setting up on the west coast, this pattern will likely persist with into next weekend, when there is some hints at a more amplified trough tries to dig in and bring in cooler weather once again. With forecast lows at all 3 of our climate sites in the low to mid 60s, record warm lows are possible.

Given the SW flow and open Gulf, precipitable water values will be well above average for this time of the year. NAEFS and EPS tables for our CWA are indicating that the pwat anomaly may be 2 to 3 standard deviations above mid April climatology, with model means between 1.25 and 1.5 inches. Ensembles have backed off somewhat of higher amounts of QPF but looking at probabilities of 2.5 inches of rain over the next 7 days, the northern Finger Lakes and along the NY Thruway corridor still has a 30% to 50% chance. Looking at odds of an inch or more of rain, the Southern Tier and northward have high probabilities(>70%) though the Wyoming Valley in NEPA is a low prob (<40%) bullseye so they may stay drier.

KEY MESSAGE 2...

With this early season heat and humidity, there is increasing confidence in severe weather this week. Right now Tuesday and Wednesday have the best chances. Tuesday, forecast soundings have 700 to 500 mb lapse rates around 7 to 8 C/km which would support vigorous updrafts in any thunderstorm that develops. CAPE values in the afternoon is over 1000 J/kg in many of the deterministic models but if you look at the whole mixed layer, it is closer to 250 to 500 J/kg. Shear of 35 to 45 knots will still be supportive of strong storms especially given the mid level lapse rates. Thee limiting factor will be the depth of the storms as the lapse rates above 500 mb are not as steep so the equilibrium level is relatively low. There could be some larger hail in storms that do develop Tuesday as there is strong winds near the EL and the steep mid level lapse rates into the hail growth zone. Timing of the 500 mb shortwave is still tough to pin down but an afternoon passage would help all the parameters line up.

Wednesday is also looking better with higher afternoon dew points helping bump up the CAPE values in models. Deterministic models are showing closer to 1500 J/kg with a few CAMs that go out far enough, as high as 2000 J/kg. MLCAPE is also higher, over 500 mb with shear sufficient, likely in the 40 to 50 knot range. Mid level lapse rates are not as impressive so winds will be the primary threat if storms can get going. There is uncertainty with a trigger for storms as the shortwave passage in models currently are a result of an MCS that develops Tuesday in the plains which are always tough to pin down days in advance.

AVIATION /12Z MONDAY THROUGH FRIDAY/

Conditions will be mainly VFR through the 12Z TAF period until after 00Z.

Light rain showers will move across mainly Central NY this morning and afternoon. Given that drier conditions are expected as similar to yesterday, the rain should be light and should not impact visibilities much. However, some MVFR to Fuel Alt ceilings are expected at RME-SYR by 16-17z.

Winds will gradually become more westerly through the morning and stay breezy with peak gusts of 25 to 30 kts.

After 00z, ceilings lower, with MVFR/Fuel Alt restrictions expected around 03-05Z.

Outlook:

Tuesday through Thursday...Restrictions possible from showers and isolated to scattered thunderstorms.

Friday...Mainly VFR; low chance for lingering showers and restrictions.

BGM WATCHES/WARNINGS/ADVISORIES

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