Alert archive / Pennsylvania / Mesoscale Discussions in 2004

Mesoscale Discussion 95

February 6, 20046 states

The Storm Prediction Center issued this mesoscale discussion at Feb 6, 2004, 12:04 AM EST for 6 states. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: Feb 6, 2004, 12:04 AM EST (05:04 UTC)
Expired: Feb 6, 2004, 6:00 AM EST
In force: 6 hr
Issued by: the Storm Prediction Center

All 92 counties

New Castle County, DE, Anne Arundel County, MD, Baltimore County, MD, Carroll County, MD, Cecil County, MD, Charles County, MD, City of Baltimore, 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, Washington County, MD, Gloucester County, NJ, Salem County, NJ, Adams County, PA, Armstrong County, PA, Bedford County, PA, Berks County, PA, Blair County, PA, Butler County, PA, Cambria County, PA, Cameron County, PA, Carbon County, PA, Centre County, PA, Chester County, PA, Clarion County, PA, Clearfield County, PA, Clinton County, PA, Columbia County, PA, Cumberland County, PA, Dauphin County, PA, Delaware County, PA, Elk County, PA, Forest County, PA, Franklin County, PA, Fulton County, PA, Huntingdon County, PA, Indiana County, PA, Jefferson County, PA, Juniata County, PA, Lancaster County, PA, Lebanon County, PA, Lehigh County, PA, Luzerne County, PA, Lycoming County, PA, Mercer County, PA, Mifflin County, PA, Montgomery County, PA, Montour County, PA, Northumberland County, PA, Perry County, PA, Potter County, PA, Schuylkill County, PA, Snyder County, PA, Somerset County, PA, Sullivan County, PA, Tioga County, PA, Union County, PA, Venango County, PA, Westmoreland County, PA, York County, PA, Arlington County, VA, Augusta County, VA, City of Alexandria, VA, City of Fairfax, VA, City of Falls Church, VA, City of Harrisonburg, VA, City of Manassas, VA, City of Manassas Park, VA, City of Staunton, VA, City of Winchester, VA, Clarke County, VA, Culpeper County, VA, Fairfax County, VA, Fauquier County, VA, Frederick County, VA, Greene County, VA, Loudoun County, VA, Madison County, VA, Page County, VA, Prince William County, VA, Rappahannock County, VA, Rockingham County, VA, Shenandoah County, VA, Stafford County, VA, Warren County, VA, Berkeley County, WV, Jefferson County, WV, Morgan County, WV

The radar

The State College radar (KCCX), 75 km from the middle of the area, began a volume at 05:05 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

Pittsburgh, PA (KPIT), launched 00:00Z, 5.1 hours before the alert went out and 157 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: 571 m above ground
0-6 km bulk shear: 58 kt
0-1 km storm-relative helicity: 438 m²/s²
0-3 km storm-relative helicity: 525 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.

565 
ACUS11 KWNS 060504
SWOMCD
SPC MCD 060504 
PAZ000-NJZ000-DEZ000-MDZ000-DCZ000-VAZ000-WVZ000-061100-

MESOSCALE DISCUSSION 0095
NWS STORM PREDICTION CENTER NORMAN OK
1104 PM CST THU FEB 05 2004

AREAS AFFECTED...NRN VA / MD NRN DE / MUCH OF PA  / SWRN NJ

CONCERNING...WINTER MIXED PRECIPITATION 

VALID 060504Z - 061100Z

SIGNIFICANT FREEZING RAIN AND SLEET WILL CONTINUE TO DEVELOP THROUGH
THE NIGHT.  HOURLY LIQUID EQUIVALENT RATES OF 0.05 - 0.10 WILL BE
COMMON.  

04Z SURFACE ANALYSIS SHOWED RIDGE IN PLACE FROM ERN NY SWD INTO ERN
PA / NJ AND NRN VA WITH SURFACE TEMPERATURES AND WET BULB
TEMPERATURES BELOW FREEZING.  INCREASING WARM ADVECTION BETWEEN
850-750 MB WILL CAUSE PRECIPITATION TO CHANGE OVER TO PREDOMINATELY
FREEZING RAIN BETWEEN 07-12Z...OVER SRN PA AND NJ...SWD INTO MD AND
NRN VA.  ETA AND RUC FORECAST SOUNDINGS ARE IN GOOD AGREEMENT WITH
THIS SCENARIO...ALONG WITH EXPERIMENTAL PRECIP TYPE ALGORITHMS.

FURTHER N OVER THE NRN HALF OF PA...PRECIPITATION WILL LIKELY BE A
MIXTURE OF SNOW AND SLEET OVER NERN PA...WITH HEAVY SNOW RATES
POSSIBLE.  DETAILED SURFACE PRESSURE TENDENCY ANALYSIS SHOWED A
RELATIVE MINIMUM IN FALLS WITHIN AN AXIS EXTENDING FROM IPT SEWD TO
TTN.  THIS COULD INDICATE AREA OF DEEPEST COLD AIR WHERE SNOW WOULD
BE MORE LIKELY.  SLEET AND FREEZING RAIN WILL PREVAIL OVER NWRN PA
WHERE SUBFREEZING AIR IS MOST SHALLOW.

..JEWELL.. 02/06/2004

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

ATTN...WFO...PHI...BGM...CTP...LWX...RNK...PBZ...CLE...

41817950 41827712 41267583 39507504 38417680 38077956
39057847 39667865 40437994 41208041

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Feb 6, 8:03 AM EST	Mesoscale Discussion	SPC	Carroll, Frederick	5 hr

Nearby

Mesoscale Discussions in Pennsylvania, 2004 Mesoscale Discussions in Virginia, 2004 Mesoscale Discussions in Maryland, 2004 Every mesoscale discussion in 2004

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.