Graphic for MPD #0669
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


Last Updated: 459 PM EDT Wed Aug 15 2018