Alert archive / Arizona / Flash Flood Warnings in 1998

Flash Flood Warning 1, NWS Tucson, AZ

February 17, 1998Pima County, Arizona

NWS Tucson, AZ issued this flash flood warning at Feb 17, 1998, 8:36 PM MST for Pima County, Arizona. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Feb 17, 1998, 8:36 PM MST (03:36 UTC)
Expired: Feb 18, 1998, 12:00 AM MST
In force: 3 hr
Issued by: NWS Tucson, AZ
Area: Whole counties

County Pima County, AZ

The radar

The Tucson radar (KEMX), 112 km from the middle of the area, began a volume at 03:39 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

Tuscon, AZ (KTUS), launched 00:00Z, 3.6 hours before the alert went out and 84 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 679 m above ground
0-6 km bulk shear: 59 kt
0-1 km storm-relative helicity: 181 m²/s²
0-3 km storm-relative helicity: 258 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 
TTAA00 KTUS 180342
FFWTUS
AZC019-180630-

BULLETIN - EAS ACTIVATION REQUESTED
SMALL STREAM FLOOD WARNING
NATIONAL WEATHER SERVICE TUCSON AZ
836 PM MST TUE FEB 17 1998

...SMALL STREAM FLOOD WARNING FOR WESTERN AND CENTRAL PIMA
COUNTY UNTIL MIDNIGHT...

SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE ACROSS PORTIONS OF
WESTERN AND CENTRAL PIMA COUNTY CAUSING WATER FLOW IN NORMALLY DRY
WASHES. WATER IN THE VAMORI WASH NEAR SELLS HAS RISEN 2 FEET SINCE
THIS AFTERNOON.

FLOODING OF LOW SPOTS IN HIGHWAYS ACROSS PORTIONS OF WESTERN AND
CENTRAL PIMA COUNTY IS LIKELY THROUGH THE REST OF THE EVENING.
SHOWERS WILL SLOWLY DIMINISH THE REST OF THE NIGHT AND WATER LEVELS
ARE EXPECTED TO SLOWLY RECEED.

COLLINS

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Tucson, AZ wrote its last area forecast discussion before this flash flood warning went out at Feb 17, 2:30 PM MST, 6 hours 6 minutes earlier.

Area forecast discussion, Feb 17, 2:30 PM MST, 6 hours 6 minutes before

SOUTHEAST ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
230 PM MST TUE FEB 17 1998

SYNOPSIS...A POWERFUL PACIFIC WINTER STORM WILL MOVE THROUGH
SOUTHEAST ARIZONA TONIGHT...BRINING VALLEY RAIN AND MOUNTAIN SNOW
SHOWERS. LOCALLY HEAVY RAIN AND SCATTERED EVENING THUNDERSTORMS WITH
SMALL HAIL AND GUSTY WINDS ARE LIKELY THIS EVENING. SHOWERS WILL
DECREASE FROM TUCSON WESTWARD EARLY WEDNESDAY MORNING...BUT A
DISTURBANCE ON THE BACKSIDE OF THIS STORM WITH KEEP UNSETTLED
WEATHER GOING IN THE FAR EAST PORTION OF THE STATE MOST OF
WEDNESDAY. HIGH PRESSURE ALOFT WILL BUILD INTO ARIZONA THURSDAY FOR
DRY AND WARMER CONDITIONS. ANOTHER STORM IS FORECAST TO MOVE INTO
ARIZONA FRIDAY.

DISCUSSION...IMPRESSIVE UPPER TROUGH WILL MOVE THROUGH THE SOUTHEAST
TONIGHT. STRONG DYNAMICS AT 700 AND 500 MB SHOULD LEAD TO THE LINE
OF SCATTERED THUNDERSTORMS AND HEAVY SHOWERS OVER WESTERN PIMA
COUNTY AND SONORA MEXICO PASSING THROUGH SOUTHEAST ARIZONA THIS
AFTERNOON AND EVENING. COLD POOL ALOFT WITH THE CENTER OF THIS STORM
WILL KEEP SHOWERS GOING MOST OF THE NIGHT BEFORE TAPERING OFF FROM
TUCSON WESTWARD EARLY WEDNESDAY MORNING. ANY SIGNIFICANT AREAS OF
MODERATE TO HEAVY RAINFALL WILL BRING THE THREAT OF FLASH
FLOODING...PARTICULARLY IN URBAN AREAS. SNOW LEVEL APPEARS TO BE
ALREADY AT 5000 FEET SO A HEAVY SNOW WARNING ABOVE THAT ELEVATION
LOOKS GOOD. WILL STICK WITH CURRENT STORM TOTALS FOR RAINFALL AND
SNOWFALL.

A SECONDARY VORTICITY MAXIMUM ROTATES THROUGH EASTERN ARIZONA
WEDNESDAY TO PROLONG THE THREAT OF SHOWERS. THESE SHOWERS WILL
MOSTLY BE ON THE LIGHT SIDE...THEREFORE EXCEPT FOR NORTHERN GREENLEE
COUNTY WILL NOT MENTION ANY ADDITIONAL ACCUMULATION. HIGH PRESSURE
ALOFT BUILDS INTO ARIZONA THURSDAY FOR DRY AND WARMER WEATHER.

THE MEDIUM RANGE MODELS ARE AT ODDS OVER THE NEXT STORM SYSTEM AT
THE END OF THE WEEK. THE MAJORITY OF THE MODELS (UKMET/ECMWF/NOGAPS)
FAVOR A FAST MOVING COLD SYSTEM FRIDAY THAT IMPACTS MAINLY NORTHERN
ARIZONA. THE MRF/AVN FAVOR A SLOWER/DEEPER/WARMER CUT OFF SYSTEM
THAT MOVES IN FROM SOUTHERN CALIFORNIA/NORTHERN BAJA SATURDAY. THE
CONSENSUS AMONG THE ARIZONA OFFICES WAS TO GO WITH THE FASTER
FORECAST FOR THIS SYSTEM. HOPE ITS NOT THE WARMER MRF/AVN SOLUTION
WITH A DEEP SNOWPACK ABOVE 6000 FEET. TUS +200. OKULSKI

TUS...HEAVY SNOW WARNING FOR ALL OF SOUTHEAST ARIZONA TONIGHT ABOVE
      5000 FEET ZNS 019-029-030-032>035.

The office that day

Everything else NWS Tucson, AZ issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Feb 18, 1:16 AM MST	Flash Flood Warning	TWC	Pima	7 hr

Nearby

Flash Flood Warnings in Arizona, 1998 Every flash flood warning in 1998

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.