Alert archive / New York / Mesoscale Discussions in 2004

Mesoscale Discussion 751

May 18, 20045 states

The Storm Prediction Center issued this mesoscale discussion at May 18, 2004, 6:24 PM EDT for 5 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
May 18, 2004, 6:24 PM EDT (22:24 UTC)
Expired
May 18, 2004, 8:30 PM EDT
In force
2 hr
Issued by
the Storm Prediction Center
All 50 counties

Berkshire County, MA, Franklin County, MA, Hampshire County, MA, Belknap County, NH, Cheshire County, NH, Grafton County, NH, Hillsborough County, NH, Merrimack County, NH, Sullivan County, NH, Albany County, NY, Broome County, NY, Cayuga County, NY, Chemung County, NY, Chenango County, NY, Columbia County, NY, Cortland County, NY, Delaware County, NY, Fulton County, NY, Greene County, NY, Madison County, NY, Montgomery County, NY, Oneida County, NY, Onondaga County, NY, Otsego County, NY, Rensselaer County, NY, Saratoga County, NY, Schenectady County, NY, Schoharie County, NY, Schuyler County, NY, Seneca County, NY, Steuben County, NY, Tioga County, NY, Tompkins County, NY, Ulster County, NY, Warren County, NY, Washington County, NY, Yates County, NY, Bradford County, PA, Cameron County, PA, Elk County, PA, Jefferson County, PA, McKean County, PA, Potter County, PA, Susquehanna County, PA, Tioga County, PA, Bennington County, VT, Orange County, VT, Rutland County, VT, Windham County, VT, Windsor County, VT

The radar

The Albany radar (KENX), 37 km from the middle of the area, began a volume at 22:26 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

Albany, NY (KALY), launched 12:00Z, 10.4 hours before the alert went out and 54 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, Albany, NY at 12:00Z on 2004-05-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 6 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, Albany, NY at 12:00Z on 2004-05-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 201 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
6 J/kg
Mixed-layer CIN
-326 J/kg
Mixed-layer LCL
662 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
201 m²/s²
0-3 km storm-relative helicity
186 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.

699 
ACUS11 KWNS 182225
SWOMCD
SPC MCD 182224 
VTZ000-CTZ000-MAZ000-NYZ000-PAZ000-NHZ000-190030-

MESOSCALE DISCUSSION 0751
NWS STORM PREDICTION CENTER NORMAN OK
0524 PM CDT TUE MAY 18 2004

AREAS AFFECTED...PORTIONS NRN PA...NY...SRN VT/NH...WRN MA

CONCERNING...SEVERE THUNDERSTORM WATCH 217...

VALID 182224Z - 190030Z

SEVERE POTENTIAL DIMINISHING OVERALL IN MOST OF WW...THOUGH ISOLATED
DAMAGING GUSTS AND MARGINALLY SEVERE HAIL POSSIBLE NEXT FEW HOURS IN
BAND FROM DELAWARE/OTSEGO COUNTIES NY ENEWD OVER PORTIONS SRN VT AND
SRN NH.  ADDITIONAL WW NOT ANTICIPATED ATTM...AND WW 217 MAY BE
CANCELED BEFORE SCHEDULED 2Z EXPIRATION IF PRESENT TRENDS CONTINUE
AS ANTICIPATED.

SFC MESOANALYSIS INDICATES THERMAL AXIS FROM NRN NJ UP HUDSON VALLEY
TO NEAR GFL...AND MOIST AXIS PARALLEL BUT SLIGHTLY FARTHER E
REACHING MAX OF 68 F SFC DEW POINT OVER SRN VT.  RUC SOUNDING
MODIFIED FOR THIS OPTIMAL OBSERVATION YIELDS APPROXIMATELY 1200 J/KG
MLCAPE...THOUGH 500-1000 APPEARS PREVALENT OVER MOST OF PRE-STORM
AREA.  EXPECT INSTABILITY TO DIMINISH BOTH WITH TIME AND WITH EWD
EXTENT...AS SFC DIABATIC HEATING AND PROGRESSIVELY WEAKER EWD
MOISTURE RESULT IN LOWER THETAE IN STORM INFLOW LAYER. 
MEANWHILE...A FEW TSTMS MAY MOVE EWD OUT OF NY WITH MARGINAL SEVERE
POTENTIAL...BUT COVERAGE/DURATION SHOULD BE INSUFFICIENT TO WARRANT
ADDITIONAL WW ISSUANCE...PARTICULARLY WITH DIMINISHING TRENDS IN
ENVIRONMENTAL INSTABILITY.

..EDWARDS.. 05/18/2004

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

ATTN...WFO...BTV...ALY...BGM...BUF...CTP...PBZ...GYX...BOX...

41087903 41527908 43097669 43617464 43797330 42057331 

43747321 44237183 43727100 42907160 42187244 42037322

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 18, 4:43 PM EDTMesoscale DiscussionSPCFranklin, Hampden, Hampshire, Worcester92 min
May 18, 12:54 PM EDTMesoscale DiscussionSPCCattaraugus66 min
May 18, 1:04 PM EDTMesoscale DiscussionSPCAlbany, Broome, Cayuga, Chemung, Chenango, Clinton and 28 more56 min
May 18, 1:50 PM EDTSevere Thunderstorm WatchSPCAlbany, Allegany, Broome, Cattaraugus, Cayuga, Chemung and 39 more8 hr
May 18, 2:54 PM EDTMesoscale DiscussionSPCBronx, Dutchess, Kings, New York, Orange, Putnam and 3 more96 min
May 18, 4:38 PM EDTMesoscale DiscussionSPCAlbany, Chenango, Cortland, Fulton, Greene, Madison and 7 more2 hr
May 18, 1:45 PM EDTSevere Thunderstorm WatchSPCAllegheny, Armstrong, Beaver, Butler, Clarion, Fayette and 6 more6 hr
May 18, 7:09 PM EDTMesoscale DiscussionSPCAllegheny, Armstrong, Beaver, Butler, Fayette, Greene and 3 more96 min
May 18, 7:49 PM EDTMesoscale DiscussionSPCChester, Delaware, Lancaster, Montgomery, Philadelphia, York2 hr

Nearby

Mesoscale Discussions in New York, 2004Mesoscale Discussions in Pennsylvania, 2004Mesoscale Discussions in New Hampshire, 2004Every 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.