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The March 01/02 Non-Winter Weather Event: Part 2. Hunter Coleman Michael W. Cammarata. METEOROLOGICAL PERSPECTIVE. What Happened to the Snow?. Deeper moisture moved east of the area quicker than expected Less moisture in the optimal snow growth region and for a limited amount of time
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The March 01/02 Non-Winter Weather Event: Part 2 Hunter Coleman Michael W. Cammarata
What Happened to the Snow? • Deeper moisture moved east of the area quicker than expected • Less moisture in the optimal snow growth region and for a limited amount of time • Air temperatures remained above freezing throughout the event • Soil temperatures were relatively mild prior to and during the event
RUC-13 00hr Cross-section at 7 PM EST Mar 1, 2009 from Greenville to Charleston • Blue solid contours represent upward vertical motion • Background image is 1000mb-500mb Relative Humidity • White contours represent temperature • Notice over Columbia the 90% and greater values of RH are mainly below the optimum snow growth temperatures of -12C to -16C • The significant lifting (omega) was in the near surface layer over Columbia but much deeper in the upstate GSP CAE CHS
RUC-13 00hr Cross-section at 10 PM EST Mar 1, 2009 from Greenville to Charleston • Blue solid contours represent upward vertical motion • Background image is 1000mb-500mb Relative Humidity • White contours represent Temperature • Notice over Columbia the optimum snow growth temperatures of -12C to -16C are well above the moisture (even down to -8C) • The significant lift (omega) remains in the upstate • Moisture within the atmospheric column is much more shallow than at 00 UTC GSP CAE CHS
RUC-13 00hr Cross-section at 1 AM EST Mar 2, 2009 from Greenville to Charleston • Blue solid contours represent upward vertical motion • Background image is 1000mb-500mb Relative Humidity • White contours represent temperature • Moisture remains very shallow, below 6000 ft • Virtually no moisture in snow growth region • Strongest lift has shifted east of Columbia and remains in the near surface layer GSP CAE CHS
850-700mb Frontogenesis at 4 PM EST Mar 1 • Purple contours represent frontogenetic forcing • Black contours represent mean height • Dashed contours represent temperature • The axis of the forcing extends from southern VA into upstate SC • Another area of forcing was located off the GA coast
850-700mb Frontogenesis at 7 PM EST Mar 1 • Purple contours represent frontogenetic forcing • Black contours represent mean height • Dashed contours represent temperature • The strongest forcing has shifted into VA with the tail end extending into upstate SC
850-700mb Frontogenesis at 10 PM EST Mar 1 • Purple contours represent frontogenetic forcing • Black contours represent mean height • Dashed contours represent temperature • Upper forcing is very limited over the midlands of SC
850-700mb Frontogenesis at 1 AM EST Mar 2 • Purple contours represent frontogenetic forcing • Black contours represent mean height • Dashed contours represent temperature • The frontogenetic forcing has shifted off the Atlantic coast
Animation of Surface Wetbulb Temperaturein hourly increments from 5 PM EST Mar 1 to 1 AM EST Mar 2 • Notice that the wetbulb temperature never reaches the freezing mark through
850 mb Pressure Analysis at 1PM EST Mar 1, 2009 • The center of the 850mb low is centered over east central Georgia • The axis of the 850mb trough extends northeastward, west of Columbia L
850 mb Pressure Analysis at 4 PM EST Mar 1, 2009 • The center of the 850mb low is now centered just west of Augusta • The axis of the 850mb trough remains west of Columbia • The ideal track of the 850mb for snow in the midlands is further to the south from Savannah to Charleston L
850 mb Pressure Analysis at 7 PM Mar 1, 2009 • The center of the 850mb low is now near Columbia • Temperatures have dropped to -4C to -5C…but surface temperatures remain in the mid to upper 30s • The axis of the 850mb trough remains west of Columbia L
850 mb Pressure Analysis at 10 PM Mar 1, 2009 • The center of the 850mb low is broader and shifted northeast of Columbia • Temperatures remain around -5C • Note the increased strength of winds in the upstate and the northerly direction • Possible downsloping starting to occur…resulting in weaker and diminishing reflectivities L
SOIL TEMPERATURES * All temperatures are well above freezing through the event
KCAE Radar Loop 7 PM EST Mar 1 to 2 AM EST Mar 2 • Bulk of the precipitation remained in the upstate • Temperatures remained above freezing when precipitation moved through • Precipitation ended shortly after midnight…earlier than expected
Snow Depth at 1 AM EST Mar 2, 2009 • The central Midlands did report snow/sleet for a very short period of time during the event but there was no snow accumulation • The northern Midlands received the highest accumulations and those were 1-2 inches
SUMMARY • Track of 850 mb low was along I-20 rather than further south and east as models projected • Lack of moisture within critical snow growth region and did not occur very long • Surface temperatures did not fall below freezing until the precipitation was almost over • Soil temperatures leading up to the event were relatively warm in the 50s