KMEM Day 6 Forecast Discussion

This forecast discussion is for the period of 6Z to 6Z spanning the 19th and 20th of March and for the location of Memphis International Airport, in Memphis, Tennessee.

Currently (18th/15Z), a deep upper level trough is in place over the southcentral portion of the United States. High clouds already present in the Memphis area. This will be a precursor to the advancing shield of rain which should be ongoing or at least just beginning at the start of the forecast period. Models are in general agreement as to the slow pace of this this system as it propagates to the east. Ample moisture is being advected from the Gulf of Mexico and massive convergence along an almost-stationary boundary that will slowly work its way into the area should produce copious amounts of precipitation. Top that off with instability-driven thunderstorms and we could be looking at high rain amounts in the 2-3" range in the early morning hours. Precipitation should finally taper off toward the end of the forecast period and will be replaced by clearing skies and much cooler, drier air.

The GFS and WRF are in line with temperatures (except in the early morning hours) while the NGM is some place else entirely. As the GFS has been handling temperatures fairly well, the maximum temperature should occur at the very beginning of the forecast period and should be in the low 60's, unless the heavy rain begins before the forecast period starts ... which could trend to a slightly lower max (upper 50's). Temperatures should stay in the mid to lower 50's throughout the day without any heating. The warm temperature advection should be over by this time and the cloudcover and precipitation will reign for temperatures. The period minimum will come at the end of the period and depending on the clearing (radiational cooling) could get down into the lower 40's.

Pressure gradients will be strong at the beginning of the period and will weaken before tightening slightly in the afternoon. Could see sustained two-minute average winds above 20kts.


Cianca