Marine Weather and Tide Forecast for Hammondsport, NY

KEY MESSAGES
1) Hot and muggy conditions are expected today into the weekend before a cold front moves through bringing less muggy air for early next week.

2) Multiple systems are expected to move across the region through Friday, bringing rain and thunderstorm chances. Some of the thunderstorms could be severe Wednesday through Friday.

DISCUSSION
KEY MESSAGE 1...

A large ridge over the eastern US with SW flow will keep advecting in warm 850 mb temperatures of 15 to 20C. With dew points in the upper 60s and low 70s, it will feel muggy with overnight lows remaining warm. Cloud cover and rain shower development will likely limit the the next couple of days look better high temperature potential and limit the heat index below advisory criteria but could get close along the I-90 corridor. If tomorrow or Friday trends sunnier, a heat advisory may be needed. A front moves through Friday into Saturday, helping to lower dew points back down into the 50s and low 60s so while temperatures remain warm, the humidity will be much lower.

KEY MESSAGE 2...

Storms that have developed this afternoon have been so far mainly pulse storms due to the lack of meaningful wind shear.
Storm cores have struggled to get the 50 dbz to -20C with so far the highest wind gusts around 30 mph. Low and mid level lapse rates have been poor so its been tough for storm downdrafts to accelerate towards the surface. Still a few of the taller storms that form later today may get some decent microburst with winds to 60 mph.

Tonight into tomorrow, a warm front lifts in with a bit of a modified elevated mixed layer moving in. Lapse rates from 500 to 700 mb have trended down somewhat from previous runs but still will need to be watched overnight for convection that starts along the warm front. Confidence is low that storms will actually fire. Shear is not very high, only around 20 to 25 knots so severe storms are not expected though elevated storms may produce some small hail.

Tomorrow, the modified elevated mixed layer moves east fairly fast with mid level lapse rates falling back to near 6C/km.
Mixed layer CAPE looks to get over 1500 for much of CNY into NEPA so there will be plenty of energy with a 500 mb vorticity wave moving through as a trigger. Forecast hodographs are pretty strait so damaging wind gusts are the main concern with any storms that fire. The weakening mid level lapse rates through the day lower the hail risk and the lack of meaningful helicity also lowers chances of any spin ups.

Friday is when the front goes through, with a line of storms likely developing along it. Mid level lapse rates will be steeper with shear increasing through the day. Hodographs are still looking fairly strait so strong wind gusts and some small hail are the main concern with the storms along the front.

AVIATION /00Z THURSDAY THROUGH MONDAY/

One last line of showers and perhaps an embedded stray thunderstorm will move near ELM, ITH over the next hour or so (until 01z)...and between 01-02z at BGM. After this, skies are expected to be sct to clear across the region.

A brief clearing period may bring fog to ELM before midnight. Temperatures will drop to the cross over dew point by around 04z, therefore included a tempo for IFR fog between 04-08z at ELM, before some more clouds moves back toward daybreak. ELM just picked up a few hundreths of rain right before sunset, so this should increase probabilities of fog.

SYR has a good chance for MVFR and possibly IFR fog to form later this evening into the overnight hours, considering the heavy rain (1.75 inches) the area saw earlier this evening. This will keep the ground wet, with plenty of trapped low level moisture under light winds. Currently have fog forming by around 02z this evening, with tempo IFR conditions possible in the 06-10z early Thursday morning period. Confidence is moderate.

RME currently seems to be the only terminal with the best chance for IFR ceilings late tonight, developing around 06z and potentially lasting into the early or mid morning hours before lifting.

All terminals should return to VFR before the mid morning hours.
Another round of showers and storms should approach the area from the west starting in the afternoon to early evening hours on Thursday; included PROB30 groups for TSRA at all of our TAF sites, except AVP for this potential (19-24z). Confidence in storm placement and timing is low to moderate at this time.

Outlook:

Thursday night through Friday Night...Scattered showers and thunderstorms may bring occasional restrictions, especially each afternoon.

Saturday into Sunday...Cold front moves through with VFR conditions likely, potential fog at ELM overnight.

Sunday afternoon and Monday... Showers return with MVFR restrictions possible.

BGM WATCHES/WARNINGS/ADVISORIES
PA...None.
NY...None.