531  
FXUS01 KWBC 222001  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
300 PM EST THU NOV 22 2018  
 
VALID 00Z FRI NOV 23 2018 - 00Z 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...  
 
AS A SERIES OF SURFACE LOW PRESSURE SYSTEMS AND FRONTS COME  
THROUGH THE WESTERN U.S. ALONG WITH UPPER-LEVEL DISTURBANCES,  
HEAVY PRECIPITATION IS EXPECTED TO CONTINUE. IN THE LOWER  
ELEVATIONS OF THE PACIFIC NORTHWEST AND NORTHERN CALIFORNIA, RAIN  
IS LIKELY, AND THERE IS A MARGINAL RISK OF EXCESSIVE  
RAINFALL/FLASH FLOODING IN PARTS OF NORTHERN CALIFORNIA AND  
SOUTHWESTERN OREGON. THERE ARE EMBEDDED SLIGHT RISKS OF EXCESSIVE  
RAINFALL OVER BURN SCARS, OVER WHICH RAIN RUNS OFF EASILY. DEBRIS  
FLOWS ARE ALSO POSSIBLE IN THOSE AREAS. BY SATURDAY, A BREAK IN  
THE HEAVY IS EXPECTED, BUT SHOWERS COULD CONTINUE. SNOWFALL-WISE,  
1 TO 2 FEET OF SNOW IS EXPECTED IN THE NORTHERN AND CENTRAL  
ROCKIES, AS WELL AS THE WASATCH AND BITTERROOT RANGE THROUGH THE  
END OF THE WEEK.  
 
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 THESE 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.  
 
TATE  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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