Ralph's Tropical Weather-RTW: ...COLD SIBERIAN AIR CONTINUES EAST AND SOUTH TODAY...BLIZZARD CONDITIONS FOR THE NORTHEAST...

MOST OF THE COUNTRY IS BITTERLY COLD AS THIS STORM CONTINUES TO TRACK NORTHEAST INTO CANADA. BLIZZARD CONDITIONS SPREADING THROUGHT THE NORTHEAST THIS MORNING. COLD AIR WILL BEGIN TO INVADE FLORIDA THIS EVENING AND INTO THE WEEKEND.

STAY TUNE TO LOCAL WEATHER MEDIA FOR YOU AREA FOR THE LATEST ON THE THIS WINTER STORM.

RTW

FLORIDA TEMPS ON CHRISTMAS DAY VIA THE EURO, GFS AND THE CMC MODEL

NATIONAL TEMPERATURE ON CHRISTMAS DAY VIA

EURO, GFS AND CMC MODELS.

Mesoscale Precipitation Discussion 1166
NWS Weather Prediction Center College Park MD
458 AM EST Fri Dec 23 2022

Areas affected...Eastern New York through Central and Southern New
England

Concerning...Heavy rainfall...Flash flooding possible

Valid 230957Z - 231557Z

SUMMARY...Heavy rains continuing to move north across eastern New
York and central/southern New England will couple with melting
snow to encourage concerns for locally enhanced runoff and
flooding this morning.

DISCUSSION...A very dynamic setup continues to unfold across the
Northeast early this morning as shortwave energy and strong warm
air advection lifts north out ahead of a strong deep layer
trough/closed low and associated Arctic cold front over the Great
Lakes and Ohio Valley.

Surface observations show a low center becoming elongated across
areas of eastern Pennsylvania as a warm front attempts to lift
inland across southern New England as a result of the deepening
and strengthening southerly flow ahead of the upstream height
falls over the Great Lakes. A very impressive low-level jet is in
place currently over eastern New York and central/southern New
England with convergent 850 mb flow of 50 to 70+ kts overrunning
this front and helping to drive enhanced Atlantic moisture
transport and isentropic ascent.

This coupled with strengthening divergence aloft is resulting in a
fairly widespread area of heavy rain across the region with some
embedded convective elements noted more recently across areas of
southeast New York (including the greater New York City
metropolitan area) where there is a small north/south axis of
elevated instability (MUCAPE values of 100 to 250 J/kg).

Over the next several hours going through late-morning, the theme
across areas of far eastern New York, and especially the interior
of New England will be heavy rains with a strong orographic focus
involving the southeast-facing slopes of the Berkshires,
Adirondacks, Green and White Mountains. In addition to this,
warming temperatures in the boundary layer from the aforementioned
strong southeast Atlantic fetch will be favoring a rapid melting
of the pre-existing snowpack on top of locally frozen ground.

The latest HRRR guidance along with the 00Z HREF members support
locally an additional 2 to 2.5 inches of rain by late-morning, and
this coupled with the melting snow over the terrain and relatively
hydrophobic ground conditions will drive increasing concerns for
enhanced runoff and flooding. Some rainfall rates especially over
far eastern New York, western Connecticut, western Massachusetts,
and southern Vermont may locally approach 1 inch/hour with some of
these stronger convective elements outside of New York City
attempting to lift north up across the interior. So, a threat for
flash flooding is on the table too aside from the broader areal
flooding concerns.