Flash Flood Warning 56, NWS Phoenix, AZ

123 
WGUS75 KPSR 101401
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
701 AM MST Tue Sep 10 2019

AZC013-101409-
/O.CAN.KPSR.FF.W.0056.000000T0000Z-190910T1630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maricopa AZ-
701 AM MST Tue Sep 10 2019

...THE FLASH FLOOD WARNING FOR MARICOPA COUNTY IS CANCELLED...

Flooding is no longer expected to pose a threat. Please continue to
heed any remaining road closures.

LAT...LON 3390 11126 3389 11126 3383 11132 3383 11139
      3384 11140 3386 11138 3389 11141 3392 11140
      3393 11142 3396 11140

$$

AZC007-101630-
/O.CON.KPSR.FF.W.0056.000000T0000Z-190910T1630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Gila AZ-
701 AM MST Tue Sep 10 2019

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 930 AM MST FOR
GILA COUNTY...

At 659 AM MST, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Up to two inches of rain has already 
fallen. Flash flooding is expected to begin shortly.

Some locations that will experience flooding include...
Punkin Center and Tonto Basin. 

This includes AZ Route 188 between mile markers 261 and 266.
 
Additional rainfall amounts of up to half an inch is possible in the 
warned area over the next couple of hours.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

A Flash Flood Warning means that flooding is imminent or occurring.
If you are in the warned area move to higher ground immediately.
Residents living along streams and creeks should take immediate
precautions to protect life and property.

&&

LAT...LON 3390 11126 3389 11126 3383 11132 3383 11139
      3384 11140 3386 11138 3389 11141 3392 11140
      3393 11142 3396 11140

$$

LJH

070 
WGUS75 KPSR 101622
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
922 AM MST Tue Sep 10 2019

AZC007-101631-
/O.EXP.KPSR.FF.W.0056.000000T0000Z-190910T1630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Gila AZ-
922 AM MST Tue Sep 10 2019

...THE FLASH FLOOD WARNING FOR GILA COUNTY WILL EXPIRE AT 930 AM
MST...

The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed any remaining road closures.

LAT...LON 3390 11126 3389 11126 3383 11132 3383 11139
      3384 11140 3386 11138 3389 11141 3392 11140
      3393 11142 3396 11140

$$

Rogers

Area Forecast Discussion
National Weather Service Phoenix AZ
514 AM MST Tue Sep 10 2019

.UPDATE...
Updated 12Z aviation discussion.

&&

.SYNOPSIS...
Cooler and more unsettled conditions will predominate across the
region through the middle of the week. A broad area of low
pressure will bring shower and thunderstorm chances across the
eastern half of Arizona with the best chances tonight into Tuesday
morning. Lingering chances will remain through early Wednesday
before drying conditions take over. Temperatures during the first
half of the week will be several degrees below seasonal normals,
but a warming trend later in the week will bring a return of above
normal temperatures by the weekend.

&&

.DISCUSSION...
A trough will continue to move east across the region through
tomorrow. Currently, the axis of this trough splits up our
forecast area into two, with better moisture profiles east of the
axis (from Maricopa county eastward). In this region, higher PW
values exist and will continue to rise through this evening before
the trough starts to push moisture farther east tomorrow. The
current dewpoint at Phoenix Sky Harbor is 70 degrees with PW values
close to 1.25 inches, which is above the 90th percent moving
average according to the SPC sounding climatology page. Current
morning analysis shows a shortwave associated with the trough
moving into central Arizona, with showers and isolated storms
developing in the proximity of the shortwave. As this shortwave
continues to move east, it will interact with substantial low-
level moisture and continue to cool heights aloft, helping to
weaken the cap. This should enhance coverage of showers and
isolated storms this morning, mainly from Phoenix eastward.
Current SPC mesoscale analysis shows 1000-2000 J/kg of MLCAPE
through later this morning across the eastern half of our forecast
area, with convective inhibition slowly diminishing. Due to this,
there is the possibility that some of these storms could become
strong to severe. The main threats with any storm will be gusty
winds, brief heavy downpours, and lightning. Current activity
will shift east into Gila county by mid to late morning.

As the aforementioned trough continues to slowly push east, a few
embedded disturbances moving through the flow could actually aid
in additional rain and storm development later this afternoon and
overnight. However, confidence still remains low on the timing
and strength of these waves and leaves us with a little
uncertainty as to what time of the day precipitation chances will
be greatest (similar scenario as yesterday and this morning). We
can say more confidently that the greatest coverage will be over
high terrain areas, north and east of Phoenix, due to enhanced
orographic lift. Either way, cooler and lower heights aloft
through Thursday will lead to below average high temperatures in
the 90s!

After the trough moves into the central United States, high
pressure will expand and move northward. Drier air will also
spread into the lower levels, limiting rain chances for the latter
part of the week. This will also lead to an increase in
temperatures Friday-Sunday, with highs rising back above seasonal
normals. There is an indication that precipitation chances will
be on the increase again by the end of this weekend into the early
part of next week. At this moment, there is very little consensus
within the models this far out and we will continue to monitor as
it gets closer. However, if we do see this increase in moisture
and storm chances, temperatures will once again be on the decline,
with high temperatures potentially back down into the 90s by next
Tuesday.

&&

.AVIATION...Updated at 1213Z.

South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:

Isolated to scattered convection and SCT-BKN ceilings down to 4-5
kft will affect all of the terminals through 14-15Z this morning
as an mid-to-upper level shortwave approaches the region. The
greatest chances for thunderstorms will be at KSDL and KDVT and
areas to the north and east where isentropic ascent is best
oriented with upsloping terrain, so we have VCTS for those sites.
Further south and east towards KPHX and KIWA, midlevel capping is
expected to generally suppress deeper convection, so we have VCSH
in for those sites. Convective chances decrease rapidly towards
the West Valley. Southerly to southeast 10 knot winds are also
expected to persist through most of the morning hours, with brief
gustiness causing crosswind impacts at KPHX and KDVT.

After 15Z, most hi-res models keep convection out of Phoenix sites
as drier air aloft moves in with the westerlies. Although there
will still be a chance for isolated convection to develop by mid-
afternoon with any another potential embedded shortwave, drier air
advecting in aloft and some remnant midlevel stability make the
chances too low to include afternoon convection in any of the TAF
sites at this time. Ceilings will gradually lift through the late
morning and afternoon hours, with only FEW-SCT 6-8 kft ceilings
by 21-22Z if not earlier. Winds will gradually veer from southerly
to S-SW by mid-afternoon and W-SW by early evening, with 20-25
knot gusts expected as strong winds aloft mix down to the surface.
Winds should subside after 06Z with convection overnight most
likely staying north and east of the terminals.

Southeast California/Southwest Arizona including KIPL and KBLH:

Strong gusty winds will be the primary aviation impact today as a
mid-to-upper level shortwave moves through the region under clear
skies. Winds will gradually veer from the S-SE this morning to
S-SW by mid-afternoon as gusts increase to 25 knots at KIPL and
30 knots at KBLH. Blowing dust may briefly reduce visibilities,
but are not currently expected to cause significant impacts. Winds
will subside below 15 knots by late evening as they back to more
southerly headings at KBLH, whereas downsloping westerlies are
expected at KIPL.

Aviation Discussion not updated for amended TAFs.

&&

.FIRE WEATHER...
Thursday through Monday:
Rain chances decrease substantively, although residual moisture
may support an isolated shower or two in the Tonto NF area. A
drying trend will drop min RH values into the 10-25% range for
most areas by the weekend with overnight recoveries at 30-50%. The
winds should be fairly light and favor typical diurnal trends.

&&

.SPOTTER INFORMATION STATEMENT...
Spotters should follow standard reporting procedures.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&

DISCUSSION...Hernandez
AVIATION...Hopper
FIRE WEATHER...Deems

Special Weather Statement
National Weather Service Phoenix AZ
347 AM MST Tue Sep 10 2019

AZZ556-557-101115-
Tonto Basin AZ-Mazatzal Mountains AZ-
347 AM MST Tue Sep 10 2019

...SIGNIFICANT WEATHER ADVISORY FOR GILA AND MARICOPA COUNTIES UNTIL
415 AM MST...

At 347 AM MST, Doppler radar was tracking a strong thunderstorm near
Tonto Basin, or 11 miles east of Round Valley, moving northeast at 25
mph.

Winds in excess of 40 mph will be possible with this storm.

Locations impacted include...
Punkin Center and Tonto Basin.

This includes AZ Route 188 between mile markers 250 and 266.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 3391 11129 3380 11115 3368 11126 3374 11140
      3394 11135
TIME...MOT...LOC 1047Z 203DEG 20KT 3377 11130

LJH

Special Weather Statement
National Weather Service Phoenix AZ
441 AM MST Tue Sep 10 2019

AZZ541-542-545-547-101230-
New River Mesa AZ-Cave Creek/New River AZ-Deer Valley AZ-
Rio Verde/Salt River AZ-
441 AM MST Tue Sep 10 2019

...SIGNIFICANT WEATHER ADVISORY FOR MARICOPA COUNTY UNTIL 530 AM
MST...

At 441 AM MST, Doppler radar was tracking a strong thunderstorm near
Cave Creek, or 10 miles southeast of New River, moving northeast at
25 mph.

Winds in excess of 40 mph will be possible with this storm.

Locations impacted include...
Phoenix, Scottsdale, New River, Cave Creek, Carefree, Desert
Mountain, Camp Creek, Horseshoe Reservoir and Seven Springs.

This includes the following highways...
AZ Interstate 17 between mile markers 219 and 223.
AZ Route 303 near mile marker 139.

LAT...LON 3367 11199 3373 11216 3403 11205 3398 11164
TIME...MOT...LOC 1141Z 206DEG 22KT 3380 11203

Hernandez