Alert archive / New York / Mesoscale Discussions in 2007

Mesoscale Discussion 902

May 27, 200721 counties in New York; 18 counties in Pennsylvania

The Storm Prediction Center issued this mesoscale discussion at May 27, 2007, 1:12 PM EDT for 21 counties in New York; 18 counties in Pennsylvania. It was in force for 93 min.

The area

The outline as issued.

The facts

Issued
May 27, 2007, 1:12 PM EDT (17:12 UTC)
Expired
May 27, 2007, 2:45 PM EDT
In force
93 min
Issued by
the Storm Prediction Center
All 39 counties

Allegany County, NY, Broome County, NY, Cattaraugus County, NY, Cayuga County, NY, Chemung County, NY, Chenango County, NY, Cortland County, NY, Delaware County, NY, Livingston County, NY, Madison County, NY, Oneida County, NY, Onondaga County, NY, Ontario County, NY, Otsego County, NY, Schuyler County, NY, Seneca County, NY, Steuben County, NY, Tioga County, NY, Tompkins County, NY, Wayne County, NY, Yates County, NY, Bradford County, PA, Cameron County, PA, Centre County, PA, Clearfield County, PA, Clinton County, PA, Elk County, PA, Forest County, PA, Jefferson County, PA, Lycoming County, PA, McKean County, PA, Montour County, PA, Potter County, PA, Sullivan County, PA, Susquehanna County, PA, Tioga County, PA, Union County, PA, Wayne County, PA, Wyoming County, PA

The radar

The Binghamton radar (KBGM), 54 km from the middle of the area, began a volume at 17:14 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Buffalo Intl Airport, NY (KBUF), launched 12:00Z, 5.2 hours before the alert went out and 187 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, Buffalo Intl Airport, NY at 12:00Z on 2007-05-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 139 joules per kilogram.LCLLFCEL10008507005003002001001 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, Buffalo Intl Airport, NY at 12:00Z on 2007-05-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 162 square meters per square second.193958Sfc1 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
139 J/kg
Mixed-layer CIN
-34 J/kg
Mixed-layer LCL
788 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
162 m²/s²
0-3 km storm-relative helicity
182 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

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

000 
ACUS11 KWNS 271712
SWOMCD
SPC MCD 271712 
NYZ000-PAZ000-271845-

MESOSCALE DISCUSSION 0902
NWS STORM PREDICTION CENTER NORMAN OK
1212 PM CDT SUN MAY 27 2007

AREAS AFFECTED...NY...PA

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 271712Z - 271845Z

ISOLATED TSTM INITIATION HAS COMMENCED ACROSS PARTS OF CNTRL NY AND
A GENERAL INCREASE IN SEVERE TSTM POTENTIAL IS EXPECTED OVER THE
NEXT HOUR OR TWO. A WATCH APPEARS POSSIBLE FOR PARTS OF THE REGION
THIS AFTERNOON.

A FEW CELLS HAVE RECENTLY ERUPTED NEAR/ALONG MESOSCALE WARM FRONT
AND WEAK WIND SHIFTS SITUATED ACROSS SRN/CNTRL NY ATTM. DOUBLE WARM
FRONTAL STRUCTURE APPEARS IN RECENT MESOANALYSIS TO THE SE OF
LO...AND A WIND SHIFT/CONFLUENCE AXIS EXTENDS SOUTH OF A WEAK
SURFACE WAVE NEAR THE SRN SHORE OF LO. WIND SHIFT HAS BEEN SPREADING
EAST ACROSS THE SRN TIER AND EXTENDS SWD INTO PA. WITH AREAS OF
STRONGER SURFACE HEATING ELIMINATING REMAINING INHIBITION ACROSS THE
AREA...THESE WEAK MESOSCALE FEATURES WILL LIKELY AID ADDITIONAL TSTM
DEVELOPMENT OVER THE NEXT FEW HOURS. OBSERVED AND MODEL SOUNDINGS
ACROSS THE REGION SHOW SOMEWHAT MARGINAL MID LEVEL LAPSE RATES THAT
ARE LIMITING GREATER CONVECTIVE INSTABILITY. HOWEVER...LOW LEVEL
MOIST ADVECTION AND STEEPENING LOW LEVEL LAPSE RATES SHOULD BOOST
INSTABILITY ENOUGH FOR AT LEAST A FEW ROBUST UPDRAFTS. CURRENT AND
FORECAST SHEAR ACROSS NY AND NRN PA WILL SUPPORT UPDRAFT
ORGANIZATION/PERSISTENCE WITH PRIMARY THREAT LIKELY COMING FROM
BOWING LINE SEGMENTS PRODUCING STRONG TO DAMAGING WINDS.

LARGER SCALE FORCING ASSOCIATED WITH THE UPPER TROUGH AND FRONT OVER
MI WILL ARRIVE ACROSS THE REGION MUCH LATER TODAY. BUT...WEAK MID
LEVEL HEIGHT FALLS AHEAD OF THIS SYSTEM WILL CONTRIBUTE TO
STEEPENING MID LEVEL LAPSE RATES...AND RESULT IN A SUBSEQUENT
INCREASE IN INSTABILITY THROUGH LATE TODAY. THE REGION MAY
EXPERIENCE A COUPLE OF ROUNDS OF STRONG TO SEVERE STORMS AS INITIAL
ACTIVITY NEAR THE WARM FRONT AND WIND SHIFTS SPREADS EWD TOWARD THE
HUDSON VALLEY/NERN PA...AND PRE-FRONTAL ACTIVITY NOW DEVELOPING OVER
OH /REF. MCD 901/ MOVES EWD INTO PARTS OF NWRN PA AND WRN NY...WITH
ACCOMPANYING WIND DAMAGE THREAT...LATER THIS AFTERNOON.

..CARBIN.. 05/27/2007

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

ATTN...WFO...ALY...BGM...BUF...CTP...PBZ...

41787483 40497798 41097932 41987919 42347851 43327692
43397532 43327481 42547468

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 27, 1:52 PM EDTSevere Thunderstorm WatchSPCBroome, Cayuga, Chemung, Chenango, Cortland, Delaware and 11 more6 hr
May 27, 6:56 PM EDTMesoscale DiscussionSPCBroome, Cayuga, Chemung, Chenango, Cortland, Delaware and 12 more2 hr
May 27, 12:45 PM EDTMesoscale DiscussionSPCAllegheny, Armstrong, Beaver, Butler, Clarion, Fayette and 10 more90 min
May 27, 4:30 PM EDTMesoscale DiscussionSPCAdams, Cumberland, Dauphin, Franklin, Juniata, Perry and 1 more60 min

Nearby

Mesoscale Discussions in New York, 2007Mesoscale Discussions in Pennsylvania, 2007Every mesoscale discussion in 2007

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.