Mesoscale Discussion 31

Issued

Jan 18, 2011, 8:01 AM EST (13:01 UTC)

Expired

Jan 18, 2011, 12:30 PM EST

In force

4 hr

Issued by

the Storm Prediction Center

The Albany radar (KENX), 86 km from the middle of the area, began a volume at 13:01 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

077 
ACUS11 KWNS 181302
SWOMCD
SPC MCD 181301
NHZ000-MAZ000-RIZ000-CTZ000-VTZ000-NYZ000-NJZ000-PAZ000-181730-

MESOSCALE DISCUSSION 0031
NWS STORM PREDICTION CENTER NORMAN OK
0701 AM CST TUE JAN 18 2011

AREAS AFFECTED...ERN PA/NRN NJ/SERN AND ERN NY/CT/RI/WRN AND CENTRAL
MA/SRN VT/SWRN NH

CONCERNING...WINTER MIXED PRECIPITATION

VALID 181301Z - 181730Z

SNOW WILL CONTINUE TO TRANSITION TO SLEET AND FREEZING RAIN FROM
SOUTH TO NORTH ACROSS THE DISCUSSION AREA.  BY 15-18Z...FREEZING
RAIN RATES 0.05-0.10 IN/HR ARE EXPECTED SOUTH OF A LINE FROM UCA TO
EEN...WITH PRECIPITATION CHANGING TO RAIN BY 15Z FROM NERN NJ TO ERN
CT AND PARTS OF RI.  MEANWHILE...FREEZING RAIN RATES AOA 0.05 IN/3
HR SHOULD DIMINISH BY 15Z ACROSS EAST CENTRAL PA AND BY 18Z IN NERN
PA.  FARTHER N...GENERALLY FROM UCA TO CENTRAL VT/NH...PRECIPITATION
SHOULD REMAIN AS MAINLY SNOW...SOME SLEET...WITH SNOWFALL RATES
INCREASING UP TO 1 IN/HR BETWEEN 15-18Z.

A SURFACE RIDGE IS EXPECTED TO REMAIN POSITIONED FROM MAINE TO NY
THROUGH THE MORNING...WHILE A COASTAL LOW LOCATED OFF THE NERN
NC/SERN VA COAST AT 12Z TRACKS NNEWD TO OFF THE DELMARVA/NJ COAST BY
18Z.  THE GEOMETRY OF THE SURFACE FEATURES WILL MAINTAIN COLD AIR
ADVECTION PER N/NELY WINDS WITH TEMPERATURES EXPECTED TO REMAIN
SUB-FREEZING ACROSS MUCH OF THE DISCUSSION AREA.  MEANWHILE...THE
RUC HAS BEEN THE PREFERRED MODEL FOR THE EVOLUTION OF THE VERTICAL
THERMAL STRATIFICATION WITH THIS WINTER EVENT THUS FAR.  LATEST
GUIDANCE MAINTAINS A STRONG SLY LLJ INTO SERN NY/SRN NEW ENGLAND
THIS MORNING RESULTING IN STRONG WAA AND AN INCREASE IN TEMPERATURES
TO ABOVE 0 C IN THE 800-900 MB LAYER.  THUS...THIS WARMING ATOP
SUB-FREEZING SURFACE TEMPERATURES WILL SUPPORT A CONTINUED
TRANSITION FROM SNOW TO SLEET/FREEZING RAIN FROM SOUTH TO NORTH.

MODELS CONTINUE TO SUGGEST PRECIPITATION SHOULD REMAIN IN THE FORM
OF MAINLY SNOW FROM UCA INTO CENTRAL VT/NH.  HOWEVER...TEMPERATURES
IN THE 800-900 MB LAYER WILL BE INCREASING THIS MORNING TO CLOSE TO
0 C TO SUPPORT SOME SLEET DEVELOPMENT.  AN INCREASE IN UPWARD
VERTICAL MOTION IS EXPECTED BY 15-18Z...GIVEN EXPECTED HEIGHT FALLS
AND AN INCREASE IN LOW LEVEL WAA ALONG THE NOSE OF A 50-60 KT SLY
LLJ.  THIS COMBINED WITH THE COLD THERMAL PROFILE SUGGESTS SNOWFALL
RATES SHOULD INCREASE.

..PETERS.. 01/18/2011

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...GYX...BOX...BTV...OKX...ALY...PHI...BGM...CTP...

LAT...LON   40277524 40277611 40747654 41987593 43097515 43667374
            44057194 43837118 43077145 42517158 41407171 41217335
            40777425 40307491 40277524

Mesoscale Discussions in New York, 2011Mesoscale Discussions in Pennsylvania, 2011Mesoscale Discussions in Connecticut, 2011Every mesoscale discussion in 2011

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.