Severe Thunderstorm Warning 151, NWS Grand Forks, ND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND
257 AM CDT SAT JUL 18 1998

1ST PERIOD DISCUSSION...TSRA CHANCES THIS AM AND LATER THIS AFTN FCST
ISSUES TDY. CURRENTLY WATCHING TSRA IN SRN MANITOBA IN ASSOC W RRQ OF
H250 7OKT JET AND SFC MOIST CNVRGNCE AXIS W WMFNT. AS TSRA SLIDES SE IT
IS ENCOUNTERING SLGTLY MORE STABLE AIRMASS AND LOWER TD/S THAN THOSE N
OF BDR. XPCT SUM ACTVTY MAY OCCUR THIS AM IN NRN ZONES BUT DON/T XPCT
SVR. OTHRWSE...IR LOOP INDICATING MID/HI CLOUD STREAKING ACRSS NW MN IN
ASSOC W JETLET W SKC S OF GFK.

BELIV NGM VERIFYING BETTER ATTM W LOCATION OF WK SFC LOW PRES NW ND AS
WELL AS ITS RH AND UVM FIELD RELATING TO CNVCTN/QPF IN SRN MAN SO WL
FOLLOW AT LEAST FOR AM PD. LATER ON TDY NGM IS FASTER W FNT...W ETA A
BIT SLOER AND AVN MUCH SLOER AND ODD W DVLPMNT OF STRNG LO PRES IN SD BY
THIS EVE. WL THEREFORE GO W ETA/NGM BLEND FOR AFTN/EVE IDEAS.
REGARDLESS...BELIV CHANCE TSRA THIS AM IN NRN ND ZONES AND NW MN BASED
ON CURRENT TRENDS AS WELL AS SUM CHANNELED PVA XPCTD IN NW MN BY 12Z.
STRNGST H85 WAA THIS AM OCCURS IN NE ND AND NW MN AND STRNG LOW LVL
THETA ADVCTN ALSO ONGOING. ADAP INDICATING STRNGTHNG SFC MOIST CNVRGNCE
SLIDING ACRSS NCNTRL ND ATTM MEETING UP W ADVCTN OF HIER SFC MXNG RATIOS
ONGOING W S WIND.

LATER ON TDY...ACTION SHUD RE-DEVELOP SLGTLY S OF THIS AM/S CNVCTN AS
CAP WEAKENS IN ERN ND W LIFTING OF SFC/H85 FNT AND A BIT OF
AMPLIFICATION TO MID-LVL TROF. LITTLE MOVMNT TO U/L LO OVER HUDSONS BAY
SENDS ANOTHER WK S/W OUR WAY THIS AFTN AS U/L RIDGE PUMPS UP TO OUR W
INCRSNG H5 NW FLO INCRSNG SHEAR PROFILES. AS SFC/H85 FNT NEAR THIS AFTN
XPCT S FLO TO ADVCT HIER TD/S INTO SRN CWA. SUM QSTN ATTM IF NR 70 TD/S
WL MAKE IT INTO CWA THIS AFTN AS LATEST MODELS ADVRTSE WKR H85 SW FLO ON
ND SIDE CWA W STRNGST H85 JET/MOIST TRNSPRT FROM FAR TO PKD LATER THIS
AFTN. CURRENT MOS RUNNING CLOSE ON TD/S AND ADVERTISE MID/UPPER 60S
THIS AFTN.

USING BLEND OF NGM/ETA TIMING BELIV SFC FNT AND ASSOC SFC MOIST
CNVRGNCE GETS TO NR GFK ARND 20Z. MODELS INDICATE LI/S -4 TO -6
ATTM...CAPES 2700 J/KG...K INDICES ARND 35 AND PWATS 1.5. ALTHO SFC
AND H85 FLO NOT THAT IMPRESSIVE...STRNG W/NW MID LVL FLO BRNGS SR
HELICITY S TO NR 200. STORM MOTION WINDS HOWEVER...YIELD 135 AT 42
KTS SO DECENT MOTION SHUD ALLEVIATE SUM OF THE HVY RAIN THREAT. WBZ
VALUES ARND 11-12K THIS AFTN/EVE...A BIT HI FOR HAIL. RECENT EVENTS
HOWEVER...YIELDED LARGE HAIL W HIER LVS ALTHO BELIV THERMODYNAMICS NOT
QUITE AS STRNG AS LAST TIME AND BUOYANCY SHUD BE JUST SLGTLY WKR. H85
THETA RIDGE POKES UP TO DVL AT 18Z W 350K VALUE THEN SLIDES ESE INTO MN
CWA LATE THIS AFTN AS STRN U/L DVRGNCE DVLPS SE ND ARND 20Z.

AREA TIME SCTNS FROM ETA/NGM POINT AGAIN TO 18Z ARND GFK AND FEW HRS
LATER ARND BJI W STRNGST UVM AND WAA FIELDS. AS TROF AMPLIFIES LATER
THIS AFTN...BELIV CNVCTN WL INCREASE IN INTENSITY AS IT SLIDES SE INTO
MUCH OF MN CWA AND ESP THIS EVE TWRD LAKES CNTRY AND THEN SRN MN TNGT W
STRNG WINDS MAIN THREAT ATTM. TEMPS THIS AFTN DEPENDENT SUMWHAT ON
CONVCTVE DEBRIS SO WL GO A BIT LOER XTRM NE ND AND NW MN WHERE MORE
CLOUD COVER XPCTD. WL HEDGE TOWARD LOWER FWC RATHER THAN HIER FAN ATTM.

FOLLOWING ARE FORECAST SUGGESTIONS ONLY. OFFICIAL FORECASTS FOUND IN
BISZFPND AND MSPZFPMN:

DVL: SCATTERED THUNDERSTORMS THIS MORNING...THEN MOSTLY SUNNY WITH
SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING THIS AFTERNOON...SOME
COULD BE SEVERE. HIGH 85 TO 90. WIND SOUTH 10 TO 15 MPH BECOMING WEST
LATE.

GFK: WIDELY SCATTERED THUNDERSTORMS THIS MORNING...THEN PARTLY SUNNY
WITH SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON...SOME COULD BE
SEVERE. HIGH IN THE MID 80S. WIND SOUTH 10 TO 15 MPH.

FAR: MOSTLY SUNNY WITH SCATTERED THUNDERSTORMS THIS AFTERNOON...SOME
COULD BE SEVERE. HIGH 85 TO 90. WIND SOUTH 10 TO 15 MPH.

MN: HCO/ROX/BDE/TVF: PARTLY SUNNY WITH SCATTERED THUNDERSTORMS...SOME
COULD BE SEVERE. HIGH 80 TO 85. WIND SOUTHWEST 10 TO 15 MPH.

BJI/DTL/PKD/FFM: MOSTLY SUNNY WITH SCATTERED THUNDERSTORMS THIS
AFTERNOON...SOME COULD BE SEVERE. HIGH 85 TO 90. WIND SOUTHWEST 10 TO
20 MPH.

SOROKA

MNZ001>009-013>017-022>024-027>032-040-NDZ006>008-014>016-024-
026>030-038-039-049-052-053-181200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS
650 AM CDT SAT JUL 18 1998

...SLIGHT RISK OF SEVERE WEATHER TODAY ACROSS EASTERN NORTH DAKOTA AND
NORTHWEST MINNESOTA...

A DEVELOPING LOW PRESSURE AREA AND ASSOCIATED WARM FRONT WILL PUSH
ACROSS EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA THIS MORNING...TO
BE FOLLOWED BY A COLD FRONT THIS AFTERNOON. WARMER AND MORE UNSTABLE
AIR WILL MOVE INTO THE REGION WITH THE WARM-FRONT...SETTING OFF
SCATTERED THUNDERSTORMS THIS MORNING MAINLY ACROSS EASTERN NORTH DAKOTA
AND NORTHWEST MINNESOTA. SOME OF THESE STORMS MAY CONTAIN LARGE HAIL.

BY THIS AFTERNOON...THE COLD FRONT WILL ENCOUNTER THE MOIST AND
UNSTABLE ATMOSPHERE AND TRIGGER MORE THUNDERSTORMS. THE STORMS THAT
DEVELOP THIS AFTERNOON WILL HAVE THE POTENTIAL TO QUICKLY BECOME
SEVERE. THE PREFERRED TIME FOR THE SEVERE WEATHER IS EXPECTED TO BE
MAINLY AFTER 2 PM FROM DEVILS LAKE TO GRAND FORKS...AFTER 3 PM IN THE
FARGO AREA...AND AFTER 5 PM WEST-CENTRAL AND THE LAKES COUNTRY OF
MINNESOTA. LARGE HAIL...DAMAGING WINDS AND AN ISOLATED TORNADO ARE ALL
POSSIBLE LATER THIS AFTERNOON AND TONIGHT.

IN ADDITION...BY THIS EVENING THE MAIN THREAT MAY ONCE AGAIN TURN
TOWARDS VERY HEAVY RAINS ACROSS THE LAKES COUNTRY AS THE STORMS SLIDE
SOUTHEAST TOWARD CENTRAL AND EVENTUALLY SOUTHERN MINNESOTA TONIGHT.
THEREFORE...A FLASH FLOOD WATCH HAS BEEN POSTED FOR THIS AREA FOR
TONIGHT.

PLEASE STAY TUNED TO NOAA WEATHER RADIO OR YOUR FAVORITE SOURCE OF
WEATHER INFORMATION ON THE POTENTIAL FOR SEVERE WEATHER LATER TODAY.
THIS HAZARDOUS WEATHER OUTLOOK WILL BE UPDATED THIS AFTERNOON IF
CONDITIONS WARRANT.

SOROKA

MNZ001>009-013>017-022>024-027>032-040-NDZ006>008-014>016-024-
026>030-038-039-049-052-053-181200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS
650 AM CDT SAT JUL 18 1998

...SLIGHT RISK OF SEVERE WEATHER TODAY ACROSS EASTERN NORTH DAKOTA AND
NORTHWEST MINNESOTA...

A DEVELOPING LOW PRESSURE AREA AND ASSOCIATED WARM FRONT WILL PUSH
ACROSS EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA THIS MORNING...TO
BE FOLLOWED BY A COLD FRONT THIS AFTERNOON. WARMER AND MORE UNSTABLE
AIR WILL MOVE INTO THE REGION WITH THE WARM-FRONT...SETTING OFF
SCATTERED THUNDERSTORMS THIS MORNING MAINLY ACROSS EASTERN NORTH DAKOTA
AND NORTHWEST MINNESOTA. SOME OF THESE STORMS MAY CONTAIN LARGE HAIL.

BY THIS AFTERNOON...THE COLD FRONT WILL ENCOUNTER THE MOIST AND
UNSTABLE ATMOSPHERE AND TRIGGER MORE THUNDERSTORMS. THE STORMS THAT
DEVELOP THIS AFTERNOON WILL HAVE THE POTENTIAL TO QUICKLY BECOME
SEVERE. THE PREFERRED TIME FOR THE SEVERE WEATHER IS EXPECTED TO BE
MAINLY AFTER 2 PM FROM DEVILS LAKE TO GRAND FORKS...AFTER 3 PM IN THE
FARGO AREA...AND AFTER 5 PM WEST-CENTRAL AND THE LAKES COUNTRY OF
MINNESOTA. LARGE HAIL...DAMAGING WINDS AND AN ISOLATED TORNADO ARE ALL
POSSIBLE LATER THIS AFTERNOON AND TONIGHT.

IN ADDITION...BY THIS EVENING THE MAIN THREAT MAY ONCE AGAIN TURN
TOWARDS VERY HEAVY RAINS ACROSS THE LAKES COUNTRY AS THE STORMS SLIDE
SOUTHEAST TOWARD CENTRAL AND EVENTUALLY SOUTHERN MINNESOTA TONIGHT.
THEREFORE...A FLASH FLOOD WATCH HAS BEEN POSTED FOR THIS AREA FOR
TONIGHT.

PLEASE STAY TUNED TO NOAA WEATHER RADIO OR YOUR FAVORITE SOURCE OF
WEATHER INFORMATION ON THE POTENTIAL FOR SEVERE WEATHER LATER TODAY.
THIS HAZARDOUS WEATHER OUTLOOK WILL BE UPDATED THIS AFTERNOON IF
CONDITIONS WARRANT.

SOROKA