Alert archive / North Dakota / Mesoscale Discussions in 2007

Mesoscale Discussion 1621

July 31, 200717 counties in North Dakota

The Storm Prediction Center issued this mesoscale discussion at Jul 31, 2007, 4:54 PM MDT for 17 counties in North Dakota. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jul 31, 2007, 4:54 PM MDT (22:54 UTC)
Expired: Jul 31, 2007, 7:00 PM MDT
In force: 2 hr
Issued by: the Storm Prediction Center

Counties Adams County, ND, Bottineau County, ND, Burleigh County, ND, Dunn County, ND, Grant County, ND, Hettinger County, ND, McHenry County, ND, McLean County, ND, Mercer County, ND, Morton County, ND, Mountrail County, ND, Oliver County, ND, Renville County, ND, Sheridan County, ND, Sioux County, ND, Stark County, ND, Ward County, ND

The nearest sounding before it

Bismarck Municip, ND (KBIS), launched 12:00Z, 10.9 hours before the alert went out and 120 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: 1616 J/kg
Mixed-layer CIN: -204 J/kg
Mixed-layer LCL: 1248 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: 95 m²/s²
0-3 km storm-relative helicity: 114 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.

000 
ACUS11 KWNS 312254
SWOMCD
SPC MCD 312254 
NDZ000-SDZ000-010100-

MESOSCALE DISCUSSION 1621
NWS STORM PREDICTION CENTER NORMAN OK
0554 PM CDT TUE JUL 31 2007

AREAS AFFECTED...WESTERN/CENTRAL ND AND FAR NORTHERN SD

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 312254Z - 010100Z

POTENTIAL FOR ISOLATED DAMAGING WIND GUSTS/SEVERE HAIL MAY INCREASE
OVER THE NEXT FEW HOURS ACROSS WESTERN/CENTRAL ND AND FAR NORTHERN
SD. EXPECTED ISOLATED/MARGINAL NATURE OF THE OVERALL THREAT SHOULD
PRECLUDE A WATCH ISSUANCE.

LATE AFTERNOON SURFACE ANALYSIS FEATURES 1003 MB SURFACE LOW
CENTERED ACROSS NORTHWEST ND...WITH ASSOCIATED SURFACE TROUGH
EXTENDING SOUTHWARD ALONG THE SD/MT/WY BORDER REGION. THE AMBIENT
AIRMASS HAS BECOME MODERATELY UNSTABLE/VERY DEEPLY MIXED ACROSS THE
WESTERN DAKOTAS...WITH TEMPERATURES IN EXCESS OF 100 F AND CLOUD
BASES ESTIMATED TO BE WELL ABOVE 10K FT PER MODIFIED 12Z BISMARCK
RAOB AND LATEST RUC SOUNDINGS. AS MAINLY MULTICELL STORMS CONTINUE
TO INCREASE IN AREAL COVERAGE EARLY THIS EVENING ACROSS WEST CENTRAL
ND/FAR NORTHERN SD...DEEPLY MIXED/HIGH DCAPE ENVIRONMENT WILL FAVOR
STRONG DOWNDRAFT POTENTIAL...WITH THE POSSIBILITY OF AT LEAST
MARGINALLY SEVERE HAIL WITH THE MORE ROBUST UPDRAFTS. MODEST WINDS
THROUGH THE LOW TO MID TROPOSPHERE SHOULD TEND TO LIMIT OVERALL
STORM ORGANIZATION...WITH EFFECTIVE BULK SHEAR GENERALLY 25-30
KT...ALTHOUGH SOMEWHAT STRONGER FLOW RESIDES NEAR THE CANADIAN
BORDER.

..GUYER.. 07/31/2007

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

ATTN...WFO...ABR...BIS...UNR...

48970185 48840033 48369998 46800025 45780132 45380290
46220340 47700316 48660263

Nearby

Mesoscale Discussions in North Dakota, 2007 Every 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.