Synopsis...
Showers and thunderstorms will be threatening today right from the start, and will not let up until Thursday Night. Severe thunderstorms and heavy rain are large threats over the next 48 hours. Some drying will take place on Friday followed by another system bringing showers and storms for the weekend and into early next week. A humid airmass will stay with us for at least the next 10 days.
Today 7/23...
In the near term, a convective complex is currently moving northeast through eastern NY state. This may or may not clip us this morning. Already it contains very heavy rainfall and some embedded severe storms but those should stay to our west. Cutoff low to our west with large damming high to our east will continue to support a southerly flow with a tropical airmass riding on its wings. Frontal boundary in central New York will progress slowly eastward. Low level moisture convergence combined with isentropic lifting and PWATs around 1.9 inches will allow heavy rainfall to develop by noontime. There is also an increased threat for severe weather. Low level instability is lacking considerable due to no solar heating, however just above this layer, CAPE is sufficient to support damaging winds with some storms today. There is also a threat for an isolated tornado. Jet stream dynamics are excellent right now and speed shear and helicity values are very high (see the Severe Weather Outlook for more details). As mentioned there will be very low solar heating today with a thick cloud deck over us all day long. High temperatures will not rise more than 10 degrees from where they are now.
Tonight...
Severe threat will not diminish so much as just transition out of the region as the next batch of heavy rain comes in. Excellent jet dynamics combined with abundant low level moisture will continue the threat for very heavy rainfall. Dew points up around 70 will limit temperatures falling much tonight. An uncomfortable night ahead for sure. Total rainfall through 6am Thu will range between 1.5 and 2 inches, with locally 3 inches where ever thunderstorms pass over.
Thursday 7/24...
Frontal boundary moves into eastern New York with cutoff low moving slowly eastward over the Great Lakes. The right rear quadrant of the jet will move over the region providing divergence aloft and with PWATs up to 2 inches, heavy rain threat will continue through at least the early afternoon with at least another 1 to 2 inches possible (See the Severe Weather Outlook for more details on flood potential). There will be a small chance for some severe thunderstorms again on Thursday with the high speed shear making it possible to get a very damaging wind gusts. The models have trended a little slower with the passage of the front, so probably will not see the heavy rain out of the region until Thursday evening, with only some scattered showers left over lingering through Thursday night. Temperatures will be kept in the upper 70's, with dew points near 70. Thursday Night could be a lot different though. With the cold front departing, airmass will dry out a little, and allow temperatures to fall to around 60.
No changes to yesterdays forecast beyond 7/24
Friday 7/25...
Cold front will be off the coast, with only some high clouds left over on Friday. With mostly sunny skies after the heavy rainfall, can still expect a moist airmass to hang around with all the water on the ground. Temperatures will reach into the mid 80's with dew points in the low 60's and overnight lows dropping to around 60.
Saturday 7/26...
A weak cold front will approach the region, causing increasing clouds and a chance of showers and thunderstorms in the late afternoon and early evening. Daytime temperatures will be slightly cooler due to cloudcover.
Sunday 7/27 - Tuesday 7/29...
The cold front will cross the region during this period triggering scattered showers each afternoon. Temperatures will reach 80 each day with continued relatively high dew points.
Wednesday 7/30 - Friday 8/1
The east will continue to be located in a trough downstream of midwest ridging which will continue an unsettled pattern along with ample low level moisture for any boundary to work off of. Wednesday could be a drier day, but it appears the short wave could amplify again bringing another round of showers and storms on Thursday or Friday.
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