Mesoscale Precipitation Discussion 0669
NWS Weather Prediction Center College Park MD
459 PM EDT Wed Aug 15 2018

Areas affected...Ext Southeast AZ...Ext. Southwest NM...

Concerning...Heavy rainfall...Flash flooding possible

Valid 152059Z - 160059Z

SUMMARY...Slow moving, heavy rainfall producing convection in
confluent 7H band.

DISCUSSION...GOES-16 Visible depicts the eroding cloud shield of
last evening's MCV that is moving lifting from Pima to Maricopa
county.  CIRA LPW 7-5H loop depicts deepest/rich moisture of .4 to
.6" PWATs along the eastern band of the exiting MCV toward
Northern Chihuahua.  A stronger closed low in Sinaloa, it
supporting a tightening of the moisture flow/deformation band
across SE AZ toward the exiting MCV.  On the eastern edge of the
deepest moisture gradient, Temps into the 80s and Tds into the 60s
and modest mid-level lapse rates support SBCAPEs to 2500 J/kg for
strong updrafts.  Given proximity to the synoptic ridge winds are
generally weak, with cloud base inflow around 10-15 maximum and
steering winds less than 10kts. As such, updrafts will likely
collapse on themselves but in the process producing 1-1.5" rain in
short duration <1hr) potentially producing flash flooding.  Given
continued surge of moisture ahead of the next vort center, outflow
boundaries that propagate north may have the opportunity to
initiate a second round of deep convection and adding rainfall
totals.

Gallina

ATTN...WFO...EPZ...TWC...

ATTN...RFC...CBRFC...WGRFC...

LAT...LON   32691068 32591013 32420963 32170921 31810853
            31310807 31290866 31291047 31261110 31521185
            31671221 31961209 32131154 32391096