Alert archive / Pennsylvania / Special Weather Statements in 2021

Special Weather Statement, NWS Philadelphia/Mount Holly

March 6, 2021Lehigh County, Pennsylvania

NWS Philadelphia/Mount Holly issued this special weather statement at Mar 6, 2021, 6:48 AM EST for Lehigh County, Pennsylvania. It was in force for 42 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Mar 6, 2021, 6:48 AM EST (11:48 UTC)
Expired
Mar 6, 2021, 7:30 AM EST
In force
42 min
Issued by
NWS Philadelphia/Mount Holly

County Lehigh County, PA

The radar

The Philadelphia radar (KDIX), 110 km from the middle of the area, began a volume at 11:51 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, 11.8 hours before the alert went out and 216 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-pSkew-T log-p diagram, Brookhaven, NY at 00:00Z on 2021-03-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Brookhaven, NY at 00:00Z on 2021-03-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -100 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
2512 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
-100 m²/s²
0-3 km storm-relative helicity
19 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

456 
WWUS81 KPHI 061148
SPSPHI

Special Weather Statement
National Weather Service Mount Holly NJ
648 AM EST Sat Mar 6 2021

PAZ061-062-105-061230-
Upper Bucks-Lehigh-Northampton-
648 AM EST Sat Mar 6 2021

...A DANGEROUS SNOW SQUALL WILL AFFECT LEHIGH...NORTHWESTERN BUCKS
AND SOUTHWESTERN NORTHAMPTON COUNTIES...

At 648 AM EST, a dangerous snow squall was located over Allentown,
moving southeast at 30 mph.

Locations impacted include...
Allentown, Bethlehem, Emmaus, Northampton, Quakertown, Perkasie,
Bedminster, Hellertown, Slatington, Tinicum, Dublin, Walnutport,
Pleasant Valley, Fricks, Neffs, Revere, Coffeetown, New Tripoli,
Zionsville and Ancient Oaks.

This includes the following highways...
 Northeast Extension between mile markers 42 and 71.
 Interstate 78 in Pennsylvania between mile markers 50 and 69.

Use extra caution if you must travel into or through this dangerous
snow squall. Rapid changes in visibility and potentially slick roads
are likely to lead to accidents. Consider delaying travel until the
squall passes your location.

LAT...LON 4078 7568 4078 7562 4046 7506 4045 7507
      4042 7506 4029 7526 4069 7581
TIME...MOT...LOC 1148Z 324DEG 26KT 4062 7547 

$$

SFJ

The office that day

Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 6, 6:50 AM ESTSpecial Weather StatementPHIMiddlesex, Somerset40 min

Nearby

Special Weather Statements in Pennsylvania, 2021Every special weather statement in 2021

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.