Alert archive / Pennsylvania / Mesoscale Discussions in 2003

Mesoscale Discussion 92

February 16, 20036 states

The Storm Prediction Center issued this mesoscale discussion at Feb 16, 2003, 7:04 PM EST for 6 states. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued: Feb 16, 2003, 7:04 PM EST (00:04 UTC)
Expired: Feb 16, 2003, 11:30 PM EST
In force: 4 hr
Issued by: the Storm Prediction Center

All 68 counties

Kent County, DE, New Castle County, DE, Sussex County, DE, Allegany County, MD, Anne Arundel County, MD, Baltimore County, MD, Calvert County, MD, Caroline County, MD, Carroll County, MD, Cecil County, MD, City of Baltimore, MD, Dorchester County, MD, Frederick County, MD, Harford County, MD, Howard County, MD, Kent County, MD, Montgomery County, MD, Prince George's County, MD, Queen Anne's County, MD, Talbot County, MD, Washington County, MD, Atlantic County, NJ, Burlington County, NJ, Camden County, NJ, Cape May County, NJ, Cumberland County, NJ, Gloucester County, NJ, Ocean County, NJ, Salem County, NJ, Adams County, PA, Bedford County, PA, Berks County, PA, Blair County, PA, Chester County, PA, Cumberland County, PA, Dauphin County, PA, Delaware County, PA, Franklin County, PA, Fulton County, PA, Huntingdon County, PA, Juniata County, PA, Lancaster County, PA, Lebanon County, PA, Mifflin County, PA, Montgomery County, PA, Perry County, PA, Philadelphia County, PA, Somerset County, PA, York County, PA, Arlington County, VA, City of Alexandria, VA, City of Fairfax, VA, City of Falls Church, VA, City of Manassas, VA, City of Manassas Park, VA, City of Winchester, VA, Clarke County, VA, Fairfax County, VA, Fauquier County, VA, Frederick County, VA, Loudoun County, VA, Prince William County, VA, Warren County, VA, Berkeley County, WV, Hampshire County, WV, Jefferson County, WV, Mineral County, WV, Morgan County, WV

The radar

The Sterling radar (KLWX), 108 km from the middle of the area, began a volume at 00:10 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

Washington/Dulle, VA (KIAD), launched 00:00Z, 0.1 hours before the alert went out and 104 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: 493 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: 403 m²/s²
0-3 km storm-relative helicity: 1245 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.

313 
ACUS11 KWNS 170004
SWOMCD
SPC MCD 170004 
PAZ000-MDZ000-NJZ000-VAZ000-DEZ000-170430-

MESOSCALE DISCUSSION 0092
NWS STORM PREDICTION CENTER NORMAN OK
0604 PM CST SUN FEB 16 2003

AREAS AFFECTED...SRN/SERN PA...MD...NRN VA...NJ...DE

CONCERNING...HEAVY SNOW 

VALID 170004Z - 170430Z

AT LEAST 2 IN/HR SNOWFALL RATES ARE LIKELY THRU THE EVENING HOURS
IN PARTS OF PA...NRN VA..NJ...AND MD. 



WV/IR IMAGERY INDICATES THE NNEWD MOVING SWATH OF GULF OF MEXICO
MOISTURE IS SHOWING INDICATIONS OF THE FORMATION OF A DRY SLOT
LIKELY ASSOCIATED WITH A 70-75 KT MID-LVL SPEED MAX.
PRESENTLY...THE AREA OF COOLEST CLOUD TOPS IS LOCATED FROM WV
NNEWD INTO PA WITH THE DRY SLOT REGION MOVING FROM SC/NC INTO WRN
VA.



PRESENT RADAR IMAGERY AND SFC OBS SHOW STRONGEST BANDING FOR THE
HEAVIEST SNOWFALL RATES ACROSS SRN NJ...SERN PA...NRN
DE...MD...INTO NRN VA. DESPITE HAVING THE AREA OF COOLEST CLOUDS
TOPS QUICKLY HEADING NNEWD AND MID LEVEL DRYING....OBSERVATIONS
AND MODEL SOLUTIONS HINT AT THE CONTINUATION OF A HEAVY SNOW
EVENT FOR THESE AREAS THRU THE EVENING HOURS. THIS IS THE RESULT
OF INCREASING 850MB ENELY FLOW OFF THE ATLANTIC / 50-55 KT BY
17/03Z / AS WELL AS SIGNS OF MID-LVL FRONTOGENETIC FORCING. THE
ETA/RUC/AND GFS ALL AGREE IN PLACING THESE AREAS IN THE HEAVIEST
SNOWFALL AXIS THRU 17/0430Z.  

..NADEN.. 02/17/2003

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

38697502 38427552 38377671 38707766 38867849 39197918
39867926 40477863 40717785 40627668 40477573 40257487
40107421 39757395 39197441

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Feb 16, 11:19 PM EST	Mesoscale Discussion	SPC	Kent, New Castle, Sussex	6 hr
Feb 16, 7:31 PM EST	Mesoscale Discussion	SPC	Calvert, Charles, Dorchester, Saint Mary's, Talbot	6 hr

Nearby

Mesoscale Discussions in Pennsylvania, 2003 Mesoscale Discussions in Maryland, 2003 Mesoscale Discussions in Virginia, 2003 Every mesoscale discussion in 2003

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.