Nw AFD

My weather nerds may appreciate this. I should release this AFD more often. I have not changed my mind.

 

 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND JUNCTION CO  
532 PM MDT SAT MAR 30 2019  
   
SHORT TERM  
(TONIGHT THROUGH SUNDAY NIGHT)  
ISSUED AT 338 PM MDT SAT MAR 30 2019  
  
A COUPLET OF LARGE HEIGHT ANOMALIES ACROSS THE HIGH LATITUDES OF  
NOAM SEEM HAVE PUT THE MODELS IN A TAILSPIN THE PAST 24 HOURS.   
THE INTEGRATED REX PATTERN DEVELOPING OVER THE INTERMOUNTAIN WEST   
THIS AFTERNOON IS ALSO WAY OFF BASE AS FAR AS PATTERN RECOGNITION   
GOES SO CONFIDENCE IS LOW GOING INTO THIS FORECAST. THE   
ANTICYCLONIC CIRCULATION OVER THE N.ROCKIES SEEMS TO BE IN CONTROL  
OF THE FLOW WITH GOES IMAGERY SHOWING AN EASTWARD DRIFT TO THE   
DEVELOPING MODCU FIELDS OVER OUR CWA. THERE IS CHANNELIZED    
VORTICITY STRETCHING FROM THE GREAT LAKES THROUGH CENTRAL COLORADO  
AND BACK INTO THE PACNW. A CYCLONIC CIRCULATION IS DEVELOPING   
OVER OUR CWA IN THE AREA OF SHEAR THAT IS RETROGRADING WESTWARD   
ON THE SOUTHERN PERIPHERY OF THE ABOVE MENTIONED HIGH PRESSURE   
CELL. THIS LOW WILL STALL OVER EASTERN UTAH THIS EVENING BEFORE   
AN UPSTREAM RIDGE MOVING ONSHORE GIVES THE WHOLE PATTERN A SHOVE   
EASTWARD. COLD...AIR IN THIS VORTICITY CHANNEL IS AND WILL AID   
INSTABILITY AS THIS COMPACT SYSTEM ACCELERATES ACROSS THE 4   
CORNERS LATE TONIGHT INTO TOMORROW. ASCENT WILL INCREASE   
DRAMATICALLY NEAR SUNRISE AS UPPER JET SUPPORT ARRIVES. THIS   
ASCENT WILL ALSO TRIGGER A LOW LEVEL RESPONSE WHICH SHOULD HELP   
PULL MOISTURE NORTHWARD. AT THE MOMENT MOISTURE AVAILABILITY IS   
CONCERNING AS LOW LEVEL DEWPOINT DEPRESSIONS ARE VERY LARGE ACROSS  
THE SOUTHERN VALLEYS AND MOUNTAINS. I HAVE NO DESIRE TO CHANGE   
MUCH BASED ON CONFIDENCE ALONE BUT THE RAPID DECREASE IN   
PRECIPITATION AMOUNTS AND THE SOUTHERN SHIFT OF THE PRECIPITATION   
TRACK IS WORRYING. HIGH MOUNTAIN PRECIPITATION WILL PERSIST   
THROUGH THE NIGHT ON OROGRAPHICS AND INSTABILITY ALONE BUT IT MAY   
NOT COME TOGETHER FOR THE MUCH OF THE LOWER ELEVATIONS UNTIL   
SUNRISE AND BEYOND. THE INGREDIENTS ARE DEFINITELY THERE FOR HEAVY  
SNOWFALL RATES IN CONVECTIVE SHOWERS THROUGH THE DAY AS THE COLD   
AIR ALOFT SHIFTS OVERHEAD THEN TO THE EAST. THIS SHOULD ALLOW FOR   
A RATHER QUICK DOWNTURN AFTER SUNSET TOMORROW WITH LAPSE RATES   
ALSO RELAXING BY A TRANSITORY RIDGE AND WARMER AIR BUILDING IN   
ALOFT.   
   
LONG TERM  
(MONDAY THROUGH SATURDAY)  
ISSUED AT 338 PM MDT SAT MAR 30 2019  
  
WARMER CONDITIONS MOVE IN FOR THE FIRST FEW DAYS OF THE NEW WEEK  
AS THIS RIDGE WORKS THROUGH THE GREAT BASIN AS IS REPLACED BY THE  
NEXT UPSTREAM KICKER TROUGH. MOISTURE MOVING IN AHEAD OF THIS  
SYSTEM AND THE DOWNSTREAM CONFLUENT FLOW OVER OUR REGION WILL LEAD  
TO SOME ISOLATED SHOWERS MONDAY NIGHT WITH THE SHOWERS BECOMING  
MORE WIDESPREAD ON THE TERRAIN THROUGH THE DAY TUESDAY AS DAYTIME   
HEATING KICKS IN. THE ACTUAL TROUGH MOVES THROUGH ON WEDNESDAY   
AND EXPECT MORE SHOWERS ACROSS THE LOWER ELEVATIONS. THIS TROUGH   
IS NOT AS COLD AS THE CURRENT ONE AND SNOW LEVELS WILL BE HIGHER   
WITH RAIN EXPECTED MOST AREAS BELOW 9000 FEET. BY WEDNESDAY   
EVENING COOLER AIR FILTERS IN ON THE BACKSIDE OF THE TROUGH AND  
SNOW LEVELS WILL DROP THROUGH DRIER AIR IS ALREADY FILTERING IN.   
THE SAME PATTERN REPEATS FOR THE END OF THE WEEK AS THE FLOW STAYS  
PROGRESSIVE. DRY THROUGH THURSDAY WITH HEIGHTS BUILDING ALOFT   
LEADS TO INCREASING SHOWERS FRIDAY AFTERNOON INTO SATURDAY AS THE   
NEXT SYSTEM WORKS INTO THE GREAT BASIN. OVERALL TEMPERATURES   
REMAIN BELOW NORMAL THROUGH THESE PERIODS OF RAINFALL AND DRIER   
DAYS.   
  

 

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