Flash Flood Warning 4, NWS Salt Lake City, UT

Issued

Jul 8, 1999, 4:21 AM MDT (10:21 UTC)

Expired

Jul 8, 1999, 7:15 AM MDT

In force

3 hr

Issued by

NWS Salt Lake City, UT

Area

Whole counties; the outline is the Mesonet’s reconstruction

County Washington County, UT

000 
TTAA00 KSLC 081024
FFWSLC
UTC053-081315-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
421 AM MDT THU JUL 8 1999

THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CENTRAL WASHINGTON COUNTY IN UTAH

* UNTIL 715 AM MDT

* AT 418 AM MDT...WEATHER SERVICE DOPPLER RADAR INDICATED VERY       
  HEAVY RAIN OVER CENTRAL PORTIONS OF WASHINGTON COUNTY DURING THE   
  PAST SEVERAL HOURS. MORE THUNDERSTORMS ARE FORECAST TO MOVE ACROSS 
  THIS REGION THROUGH 7 AM CONTRIBUTING TO THE RUNOFF.

EXCESSIVE RUNOFF FROM THIS STORM WILL CAUSE FLASH FLOODING OF SMALL
CREEKS AND STREAMS...HIGHWAYS AND UNDERPASSES. ADDITIONALLY...COUNTRY
ROADS AND FARMLANDS ALONG THE BANKS OF CREEKS AND STREAMS AND OTHER
LOW LYING AREAS ARE SUBJECT TO FLASH FLOODING.

A FLASH FLOOD WARNING MEANS THAT FLOODING IS OCCURRING OR IS
IMMINENT. MOST FLASH FLOOD DEATHS OCCUR IN AUTOMOBILES. DO NOT
ATTEMPT TO CROSS BRIDGES...DIPS...OR OTHER LOW SPOTS IF WATER COVERS
THE ROADWAY. NEVER TRY TO CROSS A FLOWING STREAM...EVEN A SMALL
ONE...ON FOOT. TO ESCAPE RISING WATER MOVE UP TO HIGHER GROUND.

TO REPORT SEVERE WEATHER HAVE THE NEAREST LAW ENFORCEMENT AGENCY 
RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE IN 
SALT LAKE CITY.

LAT...LON 3729 11396 3712 11375 3712 11328 3742 11350

NWS Salt Lake City, UT wrote its last area forecast discussion before this flash flood warning went out at Jul 8, 3:15 AM MDT, 1 hour 6 minutes earlier.

UTAH AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UTAH
315 AM MDT THU JUL 8 1999

SYNOPSIS...COOLER AND DRIER AIR IS MOVING INTO NORTHERN UTAH...WHILE
A MOIST AND UNSTABLE AIRMASS PERSISTS OVER SOUTHERN UTAH.  THIS
PATTERN WILL CHANGE LITTLE THROUGH FRIDAY.

DISCUSSION...THUNDERSTORMS CONTINUING TONIGHT OVER SOUTHERN UTAH
WHILE MUCH DRIER AIR IS MOVING INTO THE NORTH. VERY TIGHT DEW
POINT/RELATIVE HUMIDITY GRADIENT ACROSS FRONT. POSITION OF FRONT PER
UTAH MESONET AT 300 AM FROM CENTRAL DUGWAY PROVING GROUNDS TO THE
CENTRAL TOOELE VALLEY THEN NORTH ALONG THE EAST SIDE OF GSL. MESONET
STATIONS OUT ON THE SALT FLATS SHOWING DEW POINT DROPS OF 35 DEGREES
IN 1/2 HOUR AS FRONT MOVES BY THIS DRIER AIR WILL STABILIZE THE
AIRMASS OVER NORTHERN THIRD OF UTAH TODAY. MEANWHILE SOUTHERN TWO
THIRDS OF THE STATE REMAIN IN VERY MOIST AIRMASS WITH SCATTERED
CONVECTION PRODUCING HEAVY RAIN. WILL ISSUE FLASH FLOOD WATCH FOR
THIS AFTERNOON THROUGH EARLY EVENING HOURS SOUTHERN PORTION OF
FORECAST AREA. CURRENTLY WATCHING COMPLEX OF MERGING THUNDERSTORMS
OVER WASHINGTON COUNTY. THIS AREA WILL BE AT PARTICULAR RISK FOR
FLASH FLOODING THIS AFTERNOON DUE TO HEAVY RAIN THERE WEDNESDAY
EVENING AND THIS MORNING.

LITTLE CHANGE IN THE PATTERN FRIDAY EXCEPT DRIER AIR TRYING TO WORK
SOUTH THROUGH THE UINTA BASIN INTO COLORADO BASIN ON EAST SIDE.

EXTENDED PERIOD GUIDANCE CONTINUES TO SUGGEST THAT UPPER LEVEL RIDGE
WILL RETROGRADE WEST TOWARD CALIFORNIA BY TUESDAY. AIRMASS OVER
SOUTHERN UTAH MAY DRY AT THAT TIME IF NORTHERLY FLOW ALOFT DEVELOPS.

SLC 1111  CDC 8766  GIBSON

.SLC...FF WATCH SOUTHWEST AND SOUTH-CENTRAL UT THURSDAY AFTERNOON
       THROUGH 10 PM THURSDAY EVENING.

Flash Flood Warnings in Utah, 1999Every flash flood warning in 1999

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.