159  
FXUS01 KWBC 080801  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
400 AM EDT WED AUG 08 2018  
 
VALID 12Z WED AUG 08 2018 - 12Z 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 PARTS OF THE MID-ATLANTIC AND  
NORTHEAST....  
 
...RED FLAG WARNINGS CONTINUE ACROSS SOUTHERN CALIFORNIA AND THE  
CASCADES OF WASHINGTON...  
 
...HURRICANE JOHN WILL TRACK NORTHWEST NEAR THE BAJA CALIFORNIA  
PENINSULA...  
 
SCATTERED TO WIDESPREAD SHOWERS AND THUNDERSTORMS CAN BE EXPECTED  
FOR CENTRAL AND EASTERN PORTIONS OF THE COUNTRY AS A SLOW-MOVING  
COLD FRONT SHIFTS EAST AND SOUTHEAST. 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 THE RISK FOR FLASH FLOODING. 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.  
 
HURRICANE JOHN IS TRACKING NORTHWEST AND IS EXPECTED TO PASS  
OFFSHORE THE BAJA CALIFORNIA PENINSULA. MOISTURE ASSOCIATED WITH  
THIS SYSTEM WILL FEED NORTHWARD INTO THE DESERT SOUTHWEST, WITH  
WILL STEADILY INCREASE THE POSSIBILITY FOR HIGHER RAINFALL THUS  
WPC HAS A SLIGHT RISK FOR EXCESSIVE RAINFALL AND FLASH FLOODING IN  
EFFECT FOR PORTIONS OF ARIZONA AND NEW MEXICO. MEANWHILE, THE REST  
OF THE WEST WILL CONTINUE TO HOT AND MOSTLY DRY AS A RIDGE EXTENDS  
FROM THE SOUTHWEST NORTHWARD. 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.  
 
ADDITIONALLY, AN ELEVATED THREAT FOR THE SPREAD OF WILDFIRES WILL  
PERSIST. 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.  
 
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.  
 
CAMPBELL/WIX  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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