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"Weather forecast for tonight - dark."
-George Carlin

The UDHS STORMcasts are intended for educational/informational purposes only.  They combine scientific principles with a characteristic sense of humor that often pokes fun at our behavior during weather events. While intended to be informative, the STORMcasts should never be used to make life and death decisions during severe weather events.  Follow the posted bulletins from the National Weather Service and emergency management officials for appropriate actions during these events.

STORMcast Discussion 2022-03

Issued: 11Nov22

Time:  0615 EST

Good morning everybody.  As the morning models roll in for the path of Nicole's remnants, I thought I'd put out a quick Discussion on what we can expect in the Philly region as it cruises by overnight tonight.

In general, I do not think this will be a big deal other than the fact we're experiencing it in November which is pretty unusual.  As the storm tracks northward (its center is currently near Atlanta), two main things will happen.  First, the low will come in contact with a trough currently over the Midwest that will scoop it up and begin to steer it on a more northeasterly track taking what used to be the eye over central PA around 1 AM Saturday.  Second, the storm will make a structural transition from a tropical to an extratropical cyclone which will have some impact on our own weather tonight.

Severe Weather Threat

The alert map at right shows the northern edge of a large Tornado Watch posted for much of VA and the Carolinas (the yellow boxes).  Although this threat exists today, by the time the remnants of Nicole reaches our area and becomes consumed by the incoming trough, this threat should diminish considerably.  However, with a very warm air mass injected by Nicole, its associated instability, and a strong cold front approaching from the west, there's still room for a burst of isolated strong to severe weather during the overnight hours.  The threat should be short-lived and peak during the predawn hours but it cannot be ruled out entirely.  If this risk increases, we might see the Tornado Watch gradually marched further north but, at least for now, I do not see this affecting the Philly region.   Pay attention to the NWS for this development if it occurs at all.

Precipitation Estimates

Honestly, the precipitation estimates are not all that impressive with the focus of the rainfall being more focused near the center of circulation to our west.  1" to 2" seems reasonable at this point with localized street flooding possible due to all the leaves on the ground but I do not expect a widespread flooding threat.  The transition of this storm into an extratropical cyclone also means that, instead of coming as a big blob of precipitation, we'll actually get two bursts of rain with what might be a sizable gap in between.  The first shot will likely occur Friday afternoon from around lunchtime until around dinner.  This is basically an outer rain band from the original tropical system.  It will come with some downpours, wind and unusually warm temperatures for November.  

alertmap.jpg

NWS advisory map as of STORMcast issuance time.

(Map courtesy of the NWS)

HAZARDOUS WEATHER OUTLOOK - Entire forecast area for the possibility of isolated severe weather potential associated with Nicole remnants overnight Friday.

WIND ADVISORY - Coastal NJ from 11 PM to 9 AM Saturday.  20-30 mph sustained wiwinds with higher gusts expected.

After this band moves through and the storm transitions into its extratropical phase, models are suggesting a sizable dry slot might form over the region (like they sometimes do with our winter storms) for several hours this evening which might make conditions a bit more tolerable for the region's football playoff games.  I'm not sure they'll be "dry" but I do not think they'll be playing in a tropical downpour either.

Later in the overnight hours, the core of the storm will pass over PA along with a cold front attached to the Midwest trough I spoke about earlier.  Combined, these two elements will likely create another burst of moderate to heavy precipitation in the 4 AM timeframe before clearing out around daybreak.  There is a possibility for isolated severe wind gusts particularly in this part of the storm but again, it should be isolated.

Winds

Winds will be on the rise throughout the day and persist until well after the storm leaves the region on Saturday.  By lunchtime Friday, we can expect 10-15 mph sustained with higher gusts that will peak this evening around 25-30 mph.  If you still have leaves on your trees, this should finish them off.  We'll see the wind out of the south and southeast today in line with the larger counterclockwise circulation of Nicole before the cold front switches everything to the west and northwest around daybreak tomorrow.  This should give you a few hours still to strategically place your leaf piles so they blow into the neighbors' yards.

Next Week

For next week, get ready - the party's over with much more seasonable and even below normal temperatures inbound.  We should see a hard freeze over most of the area by about midweek.

Have a nice weekend everyone.

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