Area Forecast Discussion
Issued by NWS Tucson, AZ
FXUS65 KTWC 200403
Area Forecast Discussion
National Weather Service Tucson AZ
902 PM MST TUE JUL 19 2016
.SYNOPSIS...Scattered mainly afternoon and evening showers and
thunderstorms will occur again Wednesday. A decrease in coverage of
showers and thunderstorms will then prevail Thursday into this
weekend. Expect hotter daytime temperatures Thursday through
Saturday followed by a minor moderation in temperatures early next
.DISCUSSION...High pressure resides over the central and southern
plains, with Arizona on the western flank of the ridge, which is
drawing significant moisture northward across the desert southwest.
The 20/00Z KTWC sounding showed a PW of 1.39 inches. In addition,
dewpoints are currently in the upper 50s to the mid 60s.
It was a fairly active day earlier this afternoon and evening with
scattered showers and storms prompting the issuance of several
Significant Weather Advisories as well as a few Severe Thunderstorm
Warnings. Still an ongoing flood advisory through 9:15 PM for
northwest Cochise county, but another Urban and Small Stream Flood
Advisory is in effect through 10:45 pm across southern parts of
Made some adjustments to the short term POP grids to reflect the
ongoing convection and to slowly taper off the activity through the
remainder of the evening and during the overnight hours. Did keep
isolated to low end scattered showers and storms in the forecast
area-wide through the morning hours on Wednesday.
Also made some tweaks to the short term hourly temperature and
dewpoint grids to reflect the most recent trends.
For info beyond tonight, please refer to the previous discussion
.AVIATION...VALID THRU 21/06Z.
Scattered -TSRA/-SHRA this evening followed by isolated -SHRA across
the area late tonight into Wednesday morning. Expect scattered
-TSRA/-SHRA to return Wednesday afternoon. Brief wind gusts to 45
kts and MVFR conditions will occur with stronger TSRA. Surface wind
will generally be variable in direction less than 12 kts thru the
period. Aviation discussion not updated for TAF amendments.
.FIRE WEATHER...Adequate moisture for scattered afternoon and
evening thunderstorms again Wednesday. A drying trend will then lead
to reduced coverage of showers and thunderstorms Thursday into this
weekend. Moisture will remain adequate for isolated to scattered
thunderstorms early next week. Outside of gusty thunderstorm
outflows, 20-foot winds will be terrain driven and mostly less than
.PREV DISCUSSION...Have continued with scattered mainly
afternoon/evening showers/tstms again Wednesday. The 19/12Z
GFS/ECMWF/CMC were similar versus their respective solutions in
depicting a gradual daily decrease in showers/tstms to begin
Thursday and continue into this weekend. Given the progged easterly
mid-level flow, precip-free conditions area-wide should not occur as
happened earlier this month. However, moisture should remain
sufficient for isolated to scattered afternoon and evening showers
and thunderstorms Thursday through next Tuesday.
A warming trend will occur Wednesday through Friday as heights/
thicknesses increase due to a consolidation of an upper high over
southern California. Expect some minor moderation in daytime temps
early next week, but daytime temps will remain above normal.
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