White Sands Weather Forecast Office
Detailed Weather Discussion
                     
Last Updated: 1353L, 18 October 2018  by  A. Koperski
                    SYNOPSIS: PATTERN IS BECOMING SOMEWHAT STAGNANT. A DEEP TROUGH IS OVER THE SOUTHWESTERN STATES AT MID-LEVELS.  TROUGH IS BLOCKED IN PLACE BY THE LARGE SCALE UPPER RIDGEOVER THE SOUTHEASTERN STATES, PLUS A FLOW ACROSS THE TOP AT NORTHERN LATITUDES. THE HIGH PRESSURE RIDGE OVER MOST OF THE SOUTHEASTERN CONUS IS VERY DEEP IN NATURE, WITH A CLOCKWISE CIRCULATION ALOFT, EXTENDING FROM THE SURFACE TO AT LEAST 10,000 FT MSL. THE PERSISTENT SOUTHERLY FLOW ON ON THE WESTERN FLANK OF THE RIDGE CONTINUES THE INFLOW OF A VERY MOIST AIR MASS INTO THE DESERT SW.  EXPECT WHAT SHOULD BE THE FINAL SHORTWAVE OF THE SERIES TO CROSS OUR REGION TO CONTINUE THE RAINY PATTERN FROM MONDAY (22 OCT) THROUGH WED (23 OCT. HOWEVER THE MID LEVEL TROUGH IS BEGINNING TO SHEAR OUT TOWARDS THE NE, AND WEAKEN VERY RAPIDLY. NONE THE LESS, A VERY "BAGGY" TROUGHWILL REMAIN OFF THE WEST COAST, AS PART OF , AS PART OF A HIGH OVER LOW BLOCK.  MEANWHILE, ABUNDANT MOISTURE WILL REMAIN OVER SRN NM, AND MOST OF TEXAS. BY LATER FRIDAY THE SYNOPTIC PATTERN ALONG THE WEST COAST WILL HAVE EVOLVED TO ONE OF A RIDGE OVER THE PAC NW, WHILE A CLOSED LOW WILL LIE ACROSS CALIFORNIA, WITH THE BASE OF THE TROUGH WELL TO THE SOUTH OVER THE LOWER LATITUDES. A CLOSED HIGH WILL BE CENTERED OVER THE PAC NW, WHILE A CLOSED LOW WILL LIE ACROSS CALIFORNIA, WITH THE BASE OF THE TROUGH WELL TO THE SOUTH. BY MID-DAY SAT, THE PATTERN WILL BEGIN TO EVOLVE FURTHER, WITH A CLOSED HIGH OVER THE FOUR CORNERSAT MID LEVELS. ALSO A COOL-COLD HIGH(S) WILL EXIST OVER THE CENTRAL-SOUTHERN PLAINS. THE RESULTANTFLOW WILL BE DRYER AND SOMEWHAT COOLER. THE RESULT WILL BE A GRADUAL DISPLACEMENT OF THE MOIST AIRMASS SOUTHWARD. EXPECT WEST COAST RIDGING FOR CLEARING SKIES, AND AN INFLUX OF A MUCH DRYER AIR MASS FROM THE WEST TO BE COMPLETE BY THE 25'TH OR 26'TH OF THE MONTH