Alert archive / New York / Mesoscale Discussions in 2011

Mesoscale Discussion 79

February 1, 201110 counties in New Jersey; 12 counties in New York

The Storm Prediction Center issued this mesoscale discussion at Feb 1, 2011, 11:21 PM EST for 10 counties in New Jersey; 12 counties in New York. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: Feb 1, 2011, 11:21 PM EST (04:21 UTC)
Expired: Feb 2, 2011, 5:15 AM EST
In force: 6 hr
Issued by: the Storm Prediction Center

All 22 counties

Bergen County, NJ, Essex County, NJ, Hudson County, NJ, Middlesex County, NJ, Monmouth County, NJ, Morris County, NJ, Passaic County, NJ, Somerset County, NJ, Sussex County, NJ, Union County, NJ, Bronx County, NY, Dutchess County, NY, Kings County, NY, Nassau County, NY, New York County, NY, Orange County, NY, Putnam County, NY, Queens County, NY, Richmond County, NY, Rockland County, NY, Suffolk County, NY, Westchester County, NY

The radar

The Brookhaven radar (KOKX), 68 km from the middle of the area, began a volume at 04:23 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.

The nearest sounding before it

Brookhaven, NY (KOKX), launched 00:00Z, 4.4 hours before the alert went out and 68 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 467 m above ground
0-6 km bulk shear: 53 kt
0-1 km storm-relative helicity: 69 m²/s²
0-3 km storm-relative helicity: 182 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

552 
ACUS11 KWNS 020421
SWOMCD
SPC MCD 020421 
RIZ000-CTZ000-NYZ000-MAZ000-NJZ000-021015-

MESOSCALE DISCUSSION 0079
NWS STORM PREDICTION CENTER NORMAN OK
1021 PM CST TUE FEB 01 2011

AREAS AFFECTED...NERN NJ...SRN NY...LONG ISLAND INCLUDING NYC
METRO...AND CT

CONCERNING...FREEZING RAIN 

VALID 020421Z - 021015Z

FREEZING RAIN WITH RATES AROUND 0.05" TO 0.10" PER 3 HOURS WILL
DEVELOP EWD FROM PA AND WRN NJ LATE THIS EVENING. ACROSS NRN
PORTIONS OF THE MCD AREA WHERE TEMPERATURES ARE COLDER THROUGH MID
LEVELS...SLEET MAY BE THE PREDOMINATE PRECIPITATION TYPE OR MIX WITH
FREEZING RAIN.

A STRONG 850-700 MB FRONTOGENETIC BAND AHEAD OF MID LEVEL LOW
LOCATED NEAR THE CNTRL IL/IND STATE LINE AS OF 04Z WAS PARTLY
RESPONSIBLE FOR STRONG VERTICAL MOTION THROUGH WARM CONVEYOR BELT
ACROSS MUCH OF ERN OHIO AND MUCH OF PA. AS THIS SYSTEM CONTINUES TO
TRACK E/NEWD TONIGHT...CONTINUED FORCING DUE TO INCREASING MID LEVEL
JET AND VORTICITY MAX PROGRESSING THROUGH FLOW WILL HELP MAINTAIN
PRECIP SHIELD EWD ACROSS NERN NJ INTO SRN NY...LONG ISLAND AND
CT...AND WIDESPREAD FREEZING RAIN AND SLEET ARE EXPECTED. 02Z
FORECAST RUC SOUNDINGS SHOW A COLDER SFC AND MID LEVEL COLUMN OF AIR
/WARM NOSE LESS THAN 3 C/ UNTIL AFTER 12Z...THEREFORE SLEET OR A
FREEZING RAIN/SLEET MIX MAY DOMINATE. FURTHER S...A WARM NOSE OF 3-5
C SHOULD ALLOW THE PREDOMINATE PRECIP TYPE TO BE FREEZING RAIN AS
FULL MELTING OCCURS WITHIN ELEVATED WARM LAYER. WHILE SOUNDINGS DID
NOT APPEAR UNSTABLE...THE 00Z NAM INDICATED SOME WEAK SYMMETRIC
INSTABILITY WHICH COULD LEAD TO BRIEF PERIODS OF HEAVIER DOWNPOURS
WHERE RATES COULD BE HIGHER THAN THOSE MENTIONED ABOVE.

..STOPPKOTTE.. 02/02/2011

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

ATTN...WFO...BOX...OKX...ALY...PHI...

LAT...LON   41127489 41277473 41777410 41947369 42007329 42037279
            42007229 41947202 41747175 41537186 41247225 40987256
            40407341 40087426 40357459 40817485 41127489

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Feb 1, 8:39 PM EST	Mesoscale Discussion	SPC	Hunterdon, Mercer, Somerset, Warren	6 hr
Feb 2, 2:57 AM EST	Mesoscale Discussion	SPC	Clinton, Essex, Franklin, Hamilton, Herkimer, Jefferson and 4 more	4 hr

Nearby

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

Sources

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.