19.5°F
Current conditions from King Hill
Updated every 5 minutes
 
  Friday December 15, 2017

RSS Mesoscale Discussions from Storm Prediction Center

SPC - No watches are valid as of Fri Dec 15 19:49:02 UTC 2017

No watches are valid as of Fri Dec 15 19:49:02 UTC 2017.


SPC MD 1796

MD 1796 CONCERNING HEAVY SNOW FOR PARTS OF SOUTHERN/EASTERN NEW JERSEY AND LONG ISLAND
MD 1796 Image


Mesoscale Discussion 1796
NWS Storm Prediction Center Norman OK
1250 PM CST Fri Dec 15 2017

Areas affected...Parts of southern/eastern New Jersey and Long
Island

Concerning...Heavy snow 

Valid 151850Z - 152245Z

SUMMARY...Moderate snow is developing, with a 1-2 hour period of
heavy snow possible across parts of southern and eastern New Jersey,
mainly between 4-7 PM EST.

DISCUSSION...Large-scale lift supported by low-level warm advection
appears to be increasingly saturating sub-freezing thermodynamic
profiles across the northern Mid Atlantic Coast region.  Guidance
has been persistent in suggesting that increasing mid-level forcing
for ascent associated with an approaching short wave trough will
eventually contribute to increasing lift through the mixed-phased
layer most conducive to large dendritic ice crystal growth.  This is
expected to support increasing snow rates through mid to late
afternoon.  

Heaviest snow rates may focus across portions of southern and
eastern New Jersey during the 21-23Z time frame, perhaps aided by
lower/mid tropospheric frontogenetic forcing which is forecast to
strengthen while shifting off the coast, generally south of Long
Island, by early evening.  Coupled with at least a modest increase
in moisture (precipitable water increasing in excess of .4 inches),
it appears possible that snow rates could approach or exceed 1 inch
per hour for a 1 or 2 hour period at a particular location.  This
seems most probable across New Jersey coastal areas from Atlantic
City through Toms River/Lakewood in the 21-23z time frame, but
portions of the greater Philadelphia metropolitan area may also be
impacted, as well as perhaps portions of Long Island by early this
evening.

..Kerr.. 12/15/2017

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...OKX...PHI...

LAT...LON   40007515 40637344 40667225 39337326 38987471 39397544
            40007515 

Read more

SPC Dec 15, 2017 1630 UTC Day 1 Convective Outlook

SPC 1630Z Day 1 Outlook
      
Day 1 Outlook Image
Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1022 AM CST Fri Dec 15 2017

Valid 151630Z - 161200Z

...NO THUNDERSTORM AREAS FORECAST...

...SUMMARY...
The thunderstorm threat remains too low across the contiguous United
States for an outlook area through tonight.

...Synopsis and Discussion...
An upper low/trough over Ontario and the Great Lakes region will
develop eastward across the Mid-Atlantic/Northeast and Quebec
through the period. Positively tilted upper troughing extending
southward from the upper low/trough across the OH Valley into the
Mid MS Valley and southern Plains will advance generally
southeastward through tonight. Upper ridging over the western CONUS
will deamplify today as another upper trough moves eastward over the
Pacific Northwest and CA. A separate closed upper low over
northwestern Mexico will make only slow eastward progress towards TX
through early Saturday morning.

At the surface, a low is present just off the coast of the Outer
Banks of NC, and a cold front extends southwestward from this low
across the western Atlantic, northern FL Peninsula, and Gulf of
Mexico. This front will continue southeastward across the
central/southern FL Peninsula today before stalling late tonight.
While a lightning strike or two cannot be completely ruled out along
the immediate shores of Lake Erie and Ontario in western NY as lake
effect snow bands become organized late this afternoon and evening,
this potential appears highly conditional and short-lived. Overall,
thunderstorm chances across the CONUS remain too low to justify a
general thunderstorm area.

..Gleason.. 12/15/2017

Read more

SPC Dec 15, 2017 2000 UTC Day 1 Convective Outlook

SPC 2000Z Day 1 Outlook
      
Day 1 Outlook Image
Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0144 PM CST Fri Dec 15 2017

Valid 152000Z - 161200Z

...NO THUNDERSTORM AREAS FORECAST...

...SUMMARY...
No significant thunderstorm activity is expected over the contiguous
United States through tonight.

...Discussion...

Other than the possibility of an isolated strike or two downwind of
lake Erie and Ontario later this evening associated with evolving
lake effect snow bands, thunderstorm activity is not expected
through tonight over the remainder of the country.

..Dial.. 12/15/2017

.PREV DISCUSSION... /ISSUED 1022 AM CST Fri Dec 15 2017/

...Synopsis and Discussion...
An upper low/trough over Ontario and the Great Lakes region will
develop eastward across the Mid-Atlantic/Northeast and Quebec
through the period. Positively tilted upper troughing extending
southward from the upper low/trough across the OH Valley into the
Mid MS Valley and southern Plains will advance generally
southeastward through tonight. Upper ridging over the western CONUS
will deamplify today as another upper trough moves eastward over the
Pacific Northwest and CA. A separate closed upper low over
northwestern Mexico will make only slow eastward progress towards TX
through early Saturday morning.

At the surface, a low is present just off the coast of the Outer
Banks of NC, and a cold front extends southwestward from this low
across the western Atlantic, northern FL Peninsula, and Gulf of
Mexico. This front will continue southeastward across the
central/southern FL Peninsula today before stalling late tonight.
While a lightning strike or two cannot be completely ruled out along
the immediate shores of Lake Erie and Ontario in western NY as lake
effect snow bands become organized late this afternoon and evening,
this potential appears highly conditional and short-lived. Overall,
thunderstorm chances across the CONUS remain too low to justify a
general thunderstorm area.

Read more

SPC Dec 15, 2017 1730 UTC Day 2 Convective Outlook

SPC 1730Z Day 2 Outlook
      
Day 2 Outlook Image
Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1128 AM CST Fri Dec 15 2017

Valid 161200Z - 171200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Isolated thunderstorms are possible from parts of south and east
Texas Saturday and east Texas and Louisiana Saturday evening and
overnight.

...Southeast Texas coastal area...

Model consensus is that the upper low over northern Mexico will
accelerate and eject northeast through the Southern Plains later
Saturday afternoon and overnight in response to an upstream wave,
while an offshore warm front lifts north and approaches the
southeast TX coast. Stronger forcing for deep ascent will remain
well north of warm sector, but a weak surface cyclone is forecast to
develop and move northeast along the TX coast Saturday night.
Current indications are that the richer low-level moisture and warm
sector will remain just offshore with low 60s F dewpoints along the
coast. However, if the surface low and warm front can develop a
little farther northwest, there will be a small window (2-3 hours)
where a small warm sector with upper 60s F dewpoints could spread
into southeast TX including the Galveston area later Saturday night.
This scenario would support at least a marginal threat for surface
based supercells and possibly a tornado in a high shear/low cape
environment. Given the uncertainty regarding inland advance of the
warm sector, will maintain less than 5% severe probabilities this
update, but a marginal risk category might be warranted in later
outlooks.

..Dial.. 12/15/2017

Read more

SPC Day 1 Fire Weather Outlook

SPC Day 1 Fire Weather Outlook
          
Day 1 Fire Weather Outlook Image
Day 1 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
0954 AM CST Fri Dec 15 2017

Valid 151700Z - 161200Z

...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHERN CALIFORNIA...

The ongoing forecast is on track with no changes needed.  See the
previous discussion below for more information.

..Cook.. 12/15/2017

.PREV DISCUSSION... /ISSUED 0102 AM CST Fri Dec 15 2017/

...Synopsis...
...Portions of Central CA...

An upper ridge over the western U.S. will break down this period as
a shortwave trough moves over the Pacific Northwest. Overnight this
trough will dig southward, becoming oriented from southwest MT to
southern CA by Saturday morning. Strong deep-layer northerly flow on
the back side of the trough will overspread the Pacific Northwest
and much of California. Elevated to locally critical conditions are
expected to develop over the mountains and foothills in the vicinity
of the Bay Area along the central CA coast and adjacent portions of
the Sacramento Valley late in the period. In higher elevations, RH
values will begin to fall into the 20-35 percent range early
Saturday morning as sustained north winds increase to 15-25 mph with
higher gusts. 

...Portions of Southern CA...

High pressure over the Great Basin this morning will weaken later
today as the upper ridge breaks down ahead of the shortwave trough
moving into the Pacific Northwest. Gusty offshore winds will
continue across the southern CA mountains and foothills this morning
and several hours of critical conditions are expected. While wind
speeds are then expected to weaken during the afternoon and evening,
conditions will remain very dry and elevated fire weather conditions
will continue for much of the period, especially in higher
elevations where overnight RH recovery will be poor.

...Please see www.spc.noaa.gov/fire for graphic product...

Read more


 
 
Current Radar Loop:

Copyright © WestfordWeather.net 2007-2017. All rights reserved.