Jul 4, 2014 0600 UTC Day 1 Convective Outlook
Updated: Fri Jul 4 05:27:32 UTC 2014 (20140704 1200Z Day 1 shapefile | 20140704 1200Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20140704 1200 UTC Day 1 Outlook Graphic
Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 30,280 455,393 Fargo, ND...Grand Forks, ND...Moorhead, MN...West Fargo, ND...West Fargo, MN...
Probabilistic Tornado Graphic
20140704 1200 UTC Day 1 Tornado Probabilities Graphic
Probability of a tornado within 25 miles of a point.
Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.
Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 17,004 182,028 Grand Forks, ND...Devils Lake, ND...Grafton, ND...
2 % 110,819 827,441 Fargo, ND...Bismarck, ND...Moorhead, MN...Kearney, NE...North Platte, NE...
Probabilistic Damaging Wind Graphic
20140704 1200 UTC Day 1 Damaging Wind Probabilities Graphic
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point.
Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
15 % 30,468 455,378 Fargo, ND...Grand Forks, ND...Moorhead, MN...West Fargo, ND...West Fargo, MN...
5 % 253,684 3,374,164 Tucson, AZ...Casas Adobes, AZ...Catalina Foothills, AZ...Rapid City, SD...Bismarck, ND...
Probabilistic Large Hail Graphic
20140704 1200 UTC Day 1 Large Hail Probabilities Graphic
Probability of hail 1" or larger within 25 miles of a point.
Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.
Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
15 % 29,899 453,672 Fargo, ND...Grand Forks, ND...Moorhead, MN...West Fargo, ND...West Fargo, MN...
5 % 256,039 3,527,111 Tucson, AZ...Casas Adobes, AZ...Catalina Foothills, AZ...Rapid City, SD...Bismarck, ND...
   SPC AC 040527

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1227 AM CDT FRI JUL 04 2014

   VALID 041200Z - 051200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF ERN ND INTO NW MN
   THIS AFTERNOON AND EVENING...

   ...SUMMARY...
   SEVERE THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON AND EVENING ACROSS
   PARTS OF NORTHEAST NORTH DAKOTA INTO NORTHWEST MINNESOTA. STRONG
   WINDS AND HAIL WILL BE THE MAIN THREAT...BUT A TORNADO OR TWO ALSO
   IS POSSIBLE. ISOLATED TO WIDELY SCATTERED THUNDERSTORMS ARE EXPECTED
   SOUTHWARD ACROSS THE CENTRAL PLAINS...WHERE A FEW STRONG WIND GUSTS
   AND HAIL WILL BE POSSIBLE DURING THE AFTERNOON AND EVENING.
   ADDITIONAL STRONG WIND GUSTS WILL BE POSSIBLE ACROSS PARTS OF
   SOUTHERN ARIZONA WITH AFTERNOON STORMS.

   ...SYNOPSIS...

   THE UPPER TROUGH OVER THE GREAT LAKES AND APPALACHIANS WILL SHIFT
   E/NE TODAY. HURRICANE ARTHUR SHOULD START TO BECOME ABSORBED WITHIN
   THE TROUGH BY THE END OF THE PERIOD...WITH IMPACTS MOSTLY REMAINING
   OFFSHORE THE EASTERN SEABOARD. SFC HIGH PRESSURE BUILDING IN THE
   WAKE OF THE EASTERN TROUGH WILL LEAD TO WIDESPREAD STABLE CONDITIONS
   EAST OF THE MISSISSIPPI RIVER.

   ACROSS THE WESTERN AND CENTRAL U.S...A BROAD UPPER RIDGE WITH
   QUASI-ZONAL FLOW WILL OVERSPREAD THE NRN/CNTRL ROCKIES INTO THE
   NRN/CNTRL PLAINS. WEAK SHORTWAVE IMPULSES WILL TRACK EWD THROUGH THE
   RIDGE INTO THE PLAINS...AIDING IN THUNDERSTORM DEVELOPMENT IN A
   MOIST AND UNSTABLE AIRMASS DURING THE AFTERNOON AND EVENING FROM THE
   CNTRL/NRN HIGH PLAINS EASTWARD INTO THE NRN/CNTRL PLAINS. ADDITIONAL
   THUNDERSTORMS ARE EXPECTED ACROSS PARTS OF THE ARIZONA DESERTS IN
   INCREASING BOUNDARY LAYER MOISTURE ON ELY LOW LEVEL FLOW. 

   ...NRN/CNTRL PLAINS...

   SOUTHERLY LOW LEVEL FLOW WILL TRANSPORT LOW TO MID 60S DEWPOINTS
   NORTHWARD ACROSS THE PLAINS TO THE EAST OF A SFC TROUGH SITUATED N-S
   FROM THE WRN DAKOTAS INTO WRN KS BY LATE AFTERNOON. STRONG SFC
   HEATING OF THIS MOIST AIRMASS BENEATH STEEP LAPSE RATES WILL LEAD TO
   MODERATE INSTABILITY THIS AFTERNOON. DEEP LAYER SHEAR WILL BE
   ENHANCED OVER ERN ND INTO NW MN WHERE A SHORTWAVE IMPULSE WILL
   ROTATE THROUGH UPPER RIDGE...AND CLOSER PROXIMITY TO THE SFC LOW
   OVER THE S-CNTRL CANADIAN PRAIRIE WILL RESULT IN BETTER LOW LEVEL
   CONVERGENCE/BACKED SFC WINDS. 25-35 KT DEEP LAYER SHEAR SHOULD ALLOW
   FOR ORGANIZED STORM CLUSTERS CAPABLE OF LARGE HAIL AND STRONG WIND
   GUSTS. GIVEN BACKED LOW LEVEL FLOW AND MEAN MIXING RATIOS
   APPROACHING 13 G/KG...A BRIEF TORNADO OR TWO MAY BE POSSIBLE AS
   WELL. 

   FARTHER SOUTH AND WEST...THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER
   THE HIGHER TERRAIN OF THE NRN/CNTRL HIGH PLAINS AND TRACK EWD IN
   CONJUNCTION WITH A SHORTWAVE IMPULSE MOVING OUT OF THE ROCKIES AND
   INTO THE CENTRAL PLAINS. DEEP LAYER SHEAR WILL BE WEAKER...GENERALLY
   LESS THAN 25 KT...THAN THAT TO THE NORTH...AND WARMING 850-700 MB
   TEMPS MAY POSE CAPPING ISSUES. FOR THIS REASON...STORM
   LONGEVITY/ORGANIZATION AND COVERAGE ARE ALL IN QUESTION.
   HOWEVER...STEEP LAPSE RATES AND STRONG INSTABILITY WILL BE
   PRESENT...SO AT LEAST AN ISOLATED/CONDITIONAL SEVERE THREAT WILL BE
   PRESENT INTO THE EVENING HOURS. SHOULD STORMS DEVELOP AND BE
   MAINTAINED INTO THE NIGHTTIME HOURS OVER PARTS OF NEB/KS...SOME
   UPSCALE GROWTH COULD OCCUR AS THE LLJ INCREASES. ANY OVERNIGHT
   STORMS SHOULD BE ELEVATED BUT WOULD POSE A HAIL THREAT. 

   ...SE AZ...

   BOUNDARY LAYER MOISTURE WILL INCREASE OVER THE SOUTHWEST DESERTS ON
   ELY LOW TO MIDLEVEL FLOW AROUND LOW/MIDLEVEL ANTICYCLONE. STRONG SFC
   HEATING BENEATH MODEST MIDLEVEL LAPSE RATES /6.5-7.0 DEG C PER KM/
   WILL RESULT IN WEAK INSTABILITY /GENERALLY LESS THAN 1000-1500 J PER
   KG/ BY AFTERNOON AND WIDELY SCATTERED THUNDERSTORMS ARE EXPECTED.
   WEAK DEEP LAYER SHEAR WILL LIMIT OVERALL ORGANIZATION/LONGEVITY OF
   STORMS...BUT MARGINALLY SEVERE HAIL AND A FEW STRONG WIND GUSTS WILL
   BE POSSIBLE.

   ..LEITMAN.. 07/04/2014

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