textproduct: Binghamton

WHAT HAS CHANGED

Added more chances of precipitation for this morning into late morning just in case the line of showers and thunderstorms move through earlier in the day.

KEY MESSAGES

1) Threat for strong to severe thunderstorms today and tomorrow, with isolated hail and strong wind gusts possible along with heavy rain.

2) The warm pattern through the week will break down this weekend and be replaced by much colder air late in the weekend.

DISCUSSION

KEY MESSAGE 1...

The next couple of days will be warm and humid for this time of the year with 30+ knots of shear so there will be chances for some stronger thunderstorms today and tomorrow. The synoptic forcing today is very week with just a subtle 500 mb shortwave passing through so that likely will not be the main driver of the convection but will help supply the shear (35-45 knots) and steeper mid level lapse rates of around 7 C/km. Looking at what happened today in the plains, there was a cluster of supercells that developed in NW Kansas that has developed into an MCS early this morning. This was something that no models had today and even the 0Z models have struggled to handle its evolution. Given that these storms are associated with the mid level wave passing through today, it leads to less confidence in how the evolution of the storms will be today. The HRRR has trended towards an earlier line as the subsequent runs after the 0Z run have slowly started to resolve the MCS a bit better. If this does end up being the case, we may have a line of thunderstorms move through in the morning which would occur before the best CAPE development and would help stabilize the atmosphere leading to a lower end potential. Given the shear in place, a few isolated strong gusts to 50 or 60 mph would be possible with the late morning line of storms. It is possible that the rain moves through early enough for some destabilization in the mid to late afternoon though by then, the steeper mid level lapse rates are moving east.

Tomorrow is unfortunately a similar story as today in regards to how the storms may evolve. The synoptic forcing is once again weak with the primary driver of the mid level shortwave is going to be the development of MCS's in the plains this afternoon and overnight. Still, models are in better agreement that there will be more CAPE tomorrow (>1000J/kg of surface cape) and better shear (>40 knots of 0-6 km shear) so if the timing of the mid level wave that triggers the storms is early to mid afternoon, strong thunderstorms are likely and isolated supercells are possible.

We will still be in this warm SW flow pattern with frequent shortwaves on Thursday. Models do have more showers and better forcing so that looks to limit CAPE but still will need to be watched with 40+ knots of shear still present.

KEY MESSAGE 2...

While this warm, early summer like pattern persist through the first half of the weekend, Sunday into early next week has continued to trend cooler. High latitude blocking in Greenland will help a deep late season trough to dig into the Northeast US. The GFS and AIGFS both are bringing 516 to 520 dm 500 mb heights which is well below climatology for mid to late April. 850 mb temperatures also have a high probability of <-5C temperatures for Monday into Tuesday next week, with probabilities >80% for the region and >95% for CNY and north. With the Great Lakes likely warming up some over the rest of this week, it is possible they would be warm enough to generate lake effect snow with this pattern. -10C 850 mb temperature probabilities are even getting to near 50% for the Southern Tier and north and if that occurs, our day time highs may stay in the 30s to low 40s early next week. As of now, the pattern with the cold is looking dry (outside of lake effect) so despite the cold, a widespread snow event is unlikely at this time. There is still time for the pattern to change as the evolution of the Greenland blocking pattern is all over the place but a cooler stretch of weather is likely, just how cold will it get is uncertain.

AVIATION /18Z TUESDAY THROUGH SUNDAY/

Scattered showers and thunderstorms are expected to develop this afternoon and move west to east across central NY. Timing looks to be in the 19-00Z range. Included TEMPOS to account for the scattered nature and slight timing uncertainity with any thunderstorms. Any potential for thunderstorms decreases sharply after 00Z. High confidence at KRME and KSYR for the formation of MVFR/IFR ceilings overnight with a lower potential at KITH and KBGM. Any ceiling restrictions should lift out between 12-16Z Wednesday.

Outlook:

Wednesday afternoon through Friday...Restrictions possible from showers and isolated to scattered thunderstorms.

Saturday...Additional restrictions look to arrive along with showers and storms late in the day Saturday.

Sunday... Restrictions possible from showers.

BGM WATCHES/WARNINGS/ADVISORIES

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