Alert archive / Pennsylvania / Mesoscale Discussions in 2016

Mesoscale Discussion 57

January 23, 201613 counties in New Jersey; 6 counties in New York; 19 counties in Pennsylvania

The Storm Prediction Center issued this mesoscale discussion at Jan 23, 2016, 12:08 AM EST for 13 counties in New Jersey; 6 counties in New York; 19 counties in Pennsylvania. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Jan 23, 2016, 12:08 AM EST (05:08 UTC)
Expired
Jan 23, 2016, 5:15 AM EST
In force
5 hr
Issued by
the Storm Prediction Center
All 38 counties

Bergen County, NJ, Essex County, NJ, Hudson County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ, Morris County, NJ, Passaic County, NJ, Somerset County, NJ, Sussex County, NJ, Union County, NJ, Warren County, NJ, Bronx County, NY, Kings County, NY, Nassau County, NY, New York County, NY, Queens County, NY, Richmond County, NY, Adams County, PA, Berks County, PA, Bucks County, PA, Carbon County, PA, Chester County, PA, Cumberland County, PA, Dauphin County, PA, Delaware County, PA, Franklin County, PA, Lancaster County, PA, Lebanon County, PA, Lehigh County, PA, Monroe County, PA, Montgomery County, PA, Northampton County, PA, Perry County, PA, Philadelphia County, PA, Schuylkill County, PA, York County, PA

The radar

The Philadelphia radar (KDIX), 139 km from the middle of the area, began a volume at 05:08 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, 5.1 hours before the alert went out and 196 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, Washington/Dulle, VA at 00:00Z on 2016-01-23Temperature 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, Washington/Dulle, VA at 00:00Z on 2016-01-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 225 square meters per square second.1939587897117136156Sfc1 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
746 m above ground
0-6 km bulk shear
65 kt
0-1 km storm-relative helicity
225 m²/s²
0-3 km storm-relative helicity
719 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

703 
ACUS11 KWNS 230509
SWOMCD
SPC MCD 230508 
NYZ000-NJZ000-PAZ000-DEZ000-MDZ000-231015-

MESOSCALE DISCUSSION 0057
NWS STORM PREDICTION CENTER NORMAN OK
1108 PM CST FRI JAN 22 2016

AREAS AFFECTED...PORTIONS OF EASTERN PA...CENTRAL/NORTHERN NJ...AND
THE NYC METRO

CONCERNING...HEAVY SNOW 

VALID 230508Z - 231015Z

SUMMARY...MODERATE/HEAVY SNOWFALL RATES WILL GRADUALLY LIFT
NORTHWARD...IMPACTING EASTERN PA...NORTHERN/CENTRAL NJ...NYC...AND
WESTERN LONG ISLAND OVERNIGHT. SNOWFALL WILL INCREASE IN INTENSITY
OVER THE NEXT SEVERAL HOURS...ESPECIALLY TOWARDS MORNING. RATES UP
TO 1 INCH PER HOUR WILL BE POSSIBLE TONIGHT.

DISCUSSION...AS AN 850-700 MB LOW CONTINUES TO DEVELOP/DEEPEN EAST
TOWARDS THE MOUTH OF THE CHESAPEAKE TONIGHT...INTENSIFYING
ISENTROPIC ASCENT WILL COMBINE WITH DEFORMATION ALOFT TO SPREAD
MODERATE/HEAVY SNOWFALL NORTHWARD TOWARDS THE TRI-STATE AREA. SNOW
HAS ALREADY OVERSPREAD THE REGION LATE THIS EVENING...BUT GENERALLY
HAS REMAINED LIGHT/MODERATE IN INTENSITY. NONETHELESS...THE KDOX VWP
EXHIBITS A LARGE/CYCLONICALLY LOOPED HODOGRAPH...INDICATING STRONG
WARM-AIR ADVECTION WITHIN THE APPROXIMATE 1-4 KM LAYER TO THE SOUTH
OF THE REGION. MOREOVER...SFC OBS ACROSS SOUTHERN NJ SHOW PRESSURE
FALLS AROUND 2-2.5 MB/HR...LIKELY IN RESPONSE TO THE AMPLIFYING
WARM-AIR ADVECTION ALOFT. THUS...AS LARGE-SCALE ASCENT FURTHER
STRENGTHENS AND 850-700 MB FLOW INCREASES ACROSS THE DISCUSSION
AREA...IMPROVED ICE CRYSTAL GROWTH/AGGREGATION PROCESSES WILL FAVOR
SNOWFALL RATES UPWARDS OF ONE INCH PER HOUR LATE TONIGHT...MOST
LIKELY AROUND 07-10Z.

..PICCA.. 01/23/2016

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

ATTN...WFO...OKX...PHI...BGM...CTP...LWX...

LAT...LON   39727723 39707770 40017792 40607726 41057604 41227481
            41057410 40797346 39997411 39807582 39727723

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jan 22, 9:56 PM ESTMesoscale DiscussionSPCAtlantic, Burlington, Camden, Cumberland, Gloucester, Ocean and 1 more5 hr
Jan 23, 4:20 AM ESTMesoscale DiscussionSPCBergen, Burlington, Camden, Cumberland, Essex, Gloucester and 13 more5 hr
Jan 23, 8:51 AM ESTMesoscale DiscussionSPCBergen, Burlington, Camden, Essex, Gloucester, Hudson and 10 more4 hr
Jan 23, 12:44 PM ESTMesoscale DiscussionSPCAtlantic, Bergen, Burlington, Camden, Cumberland, Essex and 14 more6 hr
Jan 23, 6:40 PM ESTMesoscale DiscussionSPCAtlantic, Bergen, Burlington, Camden, Cumberland, Essex and 13 more4 hr

Nearby

Mesoscale Discussions in Pennsylvania, 2016Mesoscale Discussions in New Jersey, 2016Mesoscale Discussions in New York, 2016Every mesoscale discussion in 2016

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.