Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS01 KWNS 031631
SWODY1
SPC AC 031630

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1130 AM CDT THU SEP 03 2015

VALID 031630Z - 041200Z

...THERE IS A MRGL RISK OF SVR TSTMS THIS AFTERNOON ACROSS SE LOWER
MI...

...SUMMARY...
ISOLATED STRONG/DAMAGING GUSTS WILL BE POSSIBLE ACROSS SOUTHEAST
LOWER MICHIGAN THIS AFTERNOON.  OTHER STORMS WITH GUSTY WINDS MAY
ALSO OCCUR THIS AFTERNOON/EVENING ACROSS SOUTH CENTRAL ARIZONA.

...SYNOPSIS...
AN AMPLIFIED PATTERN OVER THE CONUS CONSISTS OF A DEEP TROUGH OVER
THE PAC NW AND A RIDGE FROM TX TO ONTARIO.  SEVERAL SMALLER-SCALE
TROUGHS ARE TRANSLATING AROUND THE ERN PERIPHERY OF THE RIDGE OVER
LOWER MI AND AL...AND THE WRN PERIPHERY OF THE RIDGE FROM THE NRN
GULF OF CA TO SRN AZ AND FROM SW CO TOWARD THE NRN HIGH PLAINS.

...S/SE LOWER MI THIS AFTERNOON...
CONVECTION ASSOCIATED WITH THE LOWER MI TROUGH WILL SPREAD SLOWLY
SEWD THROUGH THE AFTERNOON ON CONVECTIVE OUTFLOW...MAINTAINED BY
SURFACE HEATING AND THE MOISTURE/BUOYANCY NOTED IN THE 12Z DTX
SOUNDING.  MODEST ENHANCEMENT OF MIDLEVEL WLY/NWLY FLOW WITH THE
TROUGH...MLCAPE AOA 2000 J/KG...AND DCAPE NEAR 1000 J/KG COULD
SUPPORT STRONG/ISOLATED DAMAGING OUTFLOW GUSTS WITH THE CONVECTION
ACROSS S/SE LOWER MI THIS AFTERNOON.

...S CENTRAL AZ THIS AFTERNOON/EVENING...
WATER VAPOR LOOPS SUGGEST THAT A WEAK MID-UPPER SPEED MAX IS MOVING
NNEWD FROM THE NRN GULF OF CA TOWARD SRN AZ.  AN INCREASE IN
MOISTURE FROM THE S WILL CONTRIBUTE TO AN INCREASE IN CONVECTION
COMPARED TO YESTERDAY...THOUGH THE CLOUDS WILL ALSO KEEP SURFACE
TEMPERATURES COOLER.  THERE WILL BE SOME POTENTIAL FOR STORMS WITH
GUSTY OUTFLOW WINDS LATER THIS AFTERNOON/EVENING ACROSS S CENTRAL
AZ...JUST W OF THE THICKER CLOUDS WHERE SURFACE TEMPERATURES WILL BE
WARMER.  AS OF NOW...IT IS NOT CLEAR THAT LOW DAMAGING WIND
PROBABILITIES ARE NECESSARY...BUT THIS AREA WILL BE MONITORED IN
LATER UPDATES.

...SRN MAINE/NH THIS AFTERNOON...
A FEW STORMS WITH GUSTY OUTFLOW WINDS WILL BE POSSIBLE THIS
AFTERNOON AS CONVECTION FORMS OVER THE HIGHER TERRAIN AND MOVES SEWD
TOWARD THE COAST.  THE 12Z GYX SOUNDING SUPPORTS MODERATE BUOYANCY
THIS AFTERNOON...BUT THE OVERALL RISK APPEARS TOO MARGINAL TO ADD
DAMAGING WIND PROBABILITIES.

..THOMPSON/MOSIER.. 09/03/2015




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