935  
FXUS01 KWBC 072006  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
406 PM EDT TUE AUG 07 2018  
 
VALID 00Z WED AUG 08 2018 - 00Z FRI AUG 10 2018  
 
...UNSETTLED WEATHER EXPECTED TO SHIFT ACROSS THE SOUTH-CENTRAL  
AND EASTERN U.S. THROUGH MUCH OF THE WORK-WEEK...  
 
...EXCESSIVE HEAT AND AIR QUALITY CONCERNS WILL PERSIST FOR MUCH  
OF THE WESTERN U.S. AS WELL AS ACROSS THE NORTHEAST AND SOUTHEAST  
U.S....  
 
...RED FLAG WARNINGS CONTINUE ACROSS SOUTHERN CALIFORNIA AND THE  
CASCADES OF WASHINGTON...  
 
...HURRICANE JOHN WILL TRACK NORTHWEST NEAR THE BAJA CALIFORNIA  
PENINSULA...  
 
A SLOW MOVING COLD FRONT IS CURRENTLY STRETCHING FROM THE SOUTHERN  
PLAINS NORTHEAST INTO THE LOWER GREAT LAKES AND INTO THE  
NORTHEAST. AS IT SLOWLY CONTINUES TO SHIFT EAST AND SOUTHEAST, IT  
WILL REMAIN THE FOCUS FOR SCATTERED TO WIDESPREAD SHOWERS AND  
THUNDERSTORMS OVER THE COMING DAYS, BOTH ALONG THE FRONT AND AREAS  
TO THE SOUTH AND EAST. THE TRAILING END OF THE FRONT WILL SLOW  
CONSIDERABLY ACROSS THE CENTRAL U.S. SLOW STORM MOTION ALONG THIS  
PORTION OF THE FRONT WILL INCREASE THE LIKELIHOOD OF HEAVY  
RAINFALL AND FLASH FLOODING RISK. WPC HAS HIGHLIGHTED A PORTION OF  
THE SOUTHERN AND CENTRAL PLAINS (INCLUDING THE LEEWARD SIDE OF THE  
CENTRAL AND SOUTHERN ROCKIES), AS WELL AS ALONG THE OHIO RIVER AND  
INTO THE MIDDLE MISSISSIPPI VALLEY AS BEING IN A SLIGHT RISK OF  
EXCESSIVE RAINFALL. THE REMAINING REGIONS ALONG THE FRONTAL  
BOUNDARY ARE IN A MARGINAL RISK OF EXCESSIVE RAINFALL AND FLASH  
FLOODING. ADDITIONALLY, THE STORM PREDICTION CENTER HAS ISSUED A  
SLIGHT RISK FOR SEVERE STORMS FOR THE LEEWARD PORTIONS OF THE  
SOUTHERN/CENTRAL ROCKIES. A FLASH FLOOD WATCH AND SEVERE  
THUNDERSTORM WATCH ARE ALSO CURRENTLY IN PLACE FOR THIS REGION AS  
WELL. THE RISK OF EXCESSIVE RAINFALL WILL SLOWLY SHIFT SOUTHWARD  
WITH THE FRONT EACH DAY.  
 
MEANWHILE, A RIDGE HAS SETTLED OVER THE SOUTHWEST, EXTENDING  
NORTHWARD OVER MUCH OF THE WEST. THIS IS RESULTING IN DRY WEATHER,  
AS WELL AS RISING TEMPERATURES AND EXCESSIVE HEAT ACROSS MUCH OF  
THIS REGION. EXCESSIVE HEAT WARNINGS ARE IN EFFECT FOR MUCH OF THE  
SOUTHWEST AND SOUTHERN CALIFORNIA. EXCESSIVE HEAT WATCHES AND  
ADVISORIES ARE ALSO IN EFFECT FOR THE NORTHERN GREAT BASIN AND  
PORTIONS OF THE PACIFIC NORTHWEST. MANY LOCATIONS WILL OBSERVE  
DAILY MAXIMUM TEMPERATURE READINGS EXCEEDING 100 DEGREES. THESE  
HOT AND DRY CONDITIONS WILL MAINTAIN AN ELEVATED THREAT FOR THE  
SPREAD OF WILDFIRES. RED FLAG WARNINGS ARE CURRENTLY IN PLACE  
ACROSS SOUTHERN CALIFORNIA AS WELL AS ACROSS THE CASCADES IN  
WASHINGTON. AIR QUALITY ALERTS ALSO CONTINUE ACROSS PORTIONS OF  
THE SOUTHWEST, CALIFORNIA, AND NORTHWEST AS WILDFIRES CONTINUE TO  
INFUSE THE AIR WITH COPIOUS AMOUNTS OF SMOKE. A STEADY INCREASE IN  
MOISTURE IS EXPECTED OVER THE COMING DAYS FOR MEXICO AND THE  
DESERT SOUTHWEST AS HURRICANE JOHN TRACKS NORTH AND WEST IN THE  
PACIFIC OCEAN. SHOWERS AND THUNDERSTORMS MAY BE POSSIBLE FOR THE  
SOUTHWEST BY THE END OF THE WEEK.  
 
ON THE EAST COAST, STRONG SOUTHERLY FLOW WILL PUMP HOT AND HUMID  
AIR INLAND. THIS WILL RESULT IN ABOVE NORMAL TEMPERATURES AND EVEN  
HIGHER HEAT INDEX VALUES AHEAD OF THE APPROACHING COLD FRONT. HEAT  
ADVISORIES AND AIR QUALITY ALERTS FOR EXCESSIVE OZONE  
CONCENTRATIONS ARE IN EFFECT ACROSS MUCH OF THE NORTHEAST AND THE  
NORTHERN EXTENT OF THE MID-ATLANTIC REGION THROUGH THIS EVENING.  
HEAT ADVISORIES HAVE ALSO BEEN ISSUED FOR PORTIONS OF THE DEEP  
SOUTH THROUGH THIS EVENING. EXPECT CONDITIONS TO BEGIN IMPROVING  
ONCE THE COLD FRONT PASSES THROUGH IN THE COMING DAYS.  
 
WIX  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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