306  
FXUS01 KWBC 230759  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
259 AM EST FRI NOV 23 2018  
 
VALID 12Z FRI NOV 23 2018 - 12Z SUN NOV 25 2018  
 
...UNSETTLED WEATHER CONTINUES FOR THE WEST WITH HEAVY SNOW IN  
HIGHER ELEVATIONS AND HEAVY RAIN ALONG THE WEST COAST, WITH FLASH  
FLOODING AND DEBRIS FLOWS POSSIBLE OVER BURN SCARS...  
 
...WIDESPREAD RAIN IS EXPECTED IN THE MISSISSIPPI VALLEY ON  
FRIDAY, SPREADING TO THE EAST ON SATURDAY...  
 
...LIGHT FROZEN PRECIPITATION POSSIBLE IN THE SOUTHERN AND CENTRAL  
APPALACHIANS FRIDAY NIGHT INTO SATURDAY MORNING...  
 
...RECORD LOWS WILL BE WIDESPREAD ACROSS THE NORTHEAST AND  
NORTHERN MID-ATLANTIC REGION FRIDAY MORNING...  
 
MULTIPLE FRONTAL SYSTEMS ALONG WITH UPPER LEVEL DISTURBANCES WILL  
MOVE ACROSS THE WESTERN U.S. OVER THE NEXT FEW DAYS. THIS WILL  
BRING AN INCREASED AMOUNT OF PRECIPITATION IN THE AREA--WITH RAIN  
IN THE LOWER ELEVATIONS AND SNOW IN THE HIGHER ELEVATIONS OF THE  
PACIFIC NORTHWEST, NORTHERN CALIFORNIA, AND ACROSS THE  
INTERMOUNTAIN WEST. ALTHOUGH THIS RAINFALL IS BENEFICIAL FOR THE  
FIRES, BURN SCARS COULD CREATE HAZARDOUS WEATHER AND LEAD TO FLASH  
FLOODING. IN ADDITION, DEBRIS FLOWS ARE ALSO A HAZARD. THIS  
WIDESPREAD PRECIPITATION IS EXPECTED TO LAST THROUGH SATURDAY  
MORNING. BY SATURDAY EVENING AND INTO SUNDAY MORNING,  
PRECIPITATION WILL SHIFT TO PORTIONS OF THE NORTHERN AND CENTRAL  
ROCKIES IN ADDITION TO THE NORTHERN/CENTRAL PLAINS.  
 
PRECIPITATION WILL FORM BY FRIDAY MORNING AHEAD OF A DEVELOPING  
COLD FRONT IN THE CENTRAL U.S., AND AS AN UPPER-LEVEL TROUGH  
PUSHES THE FRONT EASTWARD, SPREAD INTO THE EASTERN U.S. BY  
SATURDAY. THE PRECIPITATION WILL BE MOSTLY RAIN, EXCEPT FOR SNOW  
IN THE UPPER MISSISSIPPI VALLEY ON FRIDAY EVENING INTO SATURDAY,  
AND ALSO INTO THE SOUTHERN AND CENTRAL APPALACHIANS. THERE, LIGHT  
SNOW AND FREEZING RAIN ARE FORECAST ON FRIDAY NIGHT INTO SATURDAY  
MORNING, WHICH COULD CAUSE SLICK TRAVEL CONDITIONS TEMPORARILY.  
RAIN WILL MOVE FROM THE MISSISSIPPI VALLEY ON FRIDAY INTO THE  
TENNESSEE AND OHIO VALLEYS AND SOUTHEAST ON FRIDAY NIGHT.  
GENERALLY LESS THAN AN INCH OF RAIN IS FORECAST IN THOSE AREAS.  
ON SATURDAY, RAIN WILL SPREAD INTO THE MID-ATLANTIC STATES, AND  
ABOVE AN INCH OF TOTAL PRECIPITATION COULD FALL (RAIN COMBINED  
WITH THE LIQUID EQUIVALENT OF THE LIGHT FREEZING RAIN AND SNOW) IN  
THE APPALACHIANS.  
 
A LOW PRESSURE SYSTEM WILL TRACK EASTWARD ALONG THE GULF COAST  
THROUGH THE END OF THE WEEK, LEADING TO SCATTERED SHOWERS AND  
THUNDERSTORMS ACROSS THE GULF COAST STATES ON FRIDAY. BY SATURDAY,  
THE WESTERN AND CENTRAL GULF COAST WILL DRY OUT AS THE COLD FRONT  
PASSES, WITH SHOWERS REMAINING IN FLORIDA.  
 
THE COLD TEMPERATURES FELT THIS THANKSGIVING IN THE NORTHERN  
MID-ATLANTIC AND NORTHEAST WILL CONTINUE INTO FRIDAY MORNING. LOW  
TEMPERATURES ARE EXPECTED TO REMAIN 15 TO 30 DEGREES BELOW AVERAGE  
THERE, WHICH WILL LEAD TO WIDESPREAD RECORD LOWS. TEMPERATURES  
WILL SLOWLY WARM OVER THE NEXT COUPLE OF DAYS, BUT REMAIN BELOW  
AVERAGE THROUGH THE END OF THE WEEK THERE. MEANWHILE, TEMPERATURES  
OF 5 TO 15 DEGREES ABOVE AVERAGE ARE FORECAST FOR THE CENTRAL U.S.  
 
REINHART/TATE  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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