Area Forecast Discussion
Issued by NWS Flagstaff, AZ
FXUS65 KFGZ 231618
Area Forecast Discussion
National Weather Service Flagstaff AZ
918 AM MST SAT JUL 23 2016
.SYNOPSIS...Expect a chance of showers and thunderstorms each day,
mainly along and south of the Mogollon Rim with drier conditions
to the north. Very hot afternoon temperatures are in store this
weekend for elevations below 4000 feet.
.UPDATE...Less moisture is present this morning, mainly from the
Flagstaff area northward, than what we have seen the past several
days. The precipitable water value on this mornings Flagstaff
sounding was 0.71 inches compared to 0.92 inches on Friday
morning`s sounding. Most of the drying has occurred in the low
levels (below 600 mb).
There should still be enough moisture present for scattered
storms to form this afternoon (Noon - 2 PM MST) from Flagstaff
southeastward to the White Mountains. Coverage will likely be
greatest across southern Navajo and Apache counties. Isolated
showers and storms will form elsewhere. With an inverted V
sounding profile, any storm that forms will be capable of
producing wind gusts to around 40 mph, along with small hail and
locally heavy rain. The previous forecast looks good, and no
changes are necessary.
.PREV DISCUSSION /437 AM MST/...An elongated and fairly strong
ridge stretches across the southwest United States this morning.
With this ridge overhead, the flow aloft is light so much of the
moisture that has been in the area the past few days will linger,
leading to another chance of showers and thunderstorms today. The
better chances will be along/southeast of a Flagstaff to Window
Rock line. Areas below 4000 feet are under an Excessive Heat
Warning today with very hot temperatures of 107 to 115.
The center of high pressure shifts to the four corners area for
Sunday into Tuesday. Flow around the ridge could push some
additional moisture farther north and west and lead to a bit
higher storm chances. From Wednesday through Friday, models are in
good agreement in the center of the high shifting toward Nevada,
placing northern Arizona in an east to northeast flow aloft.
Deeper moisture is likely to linger along or just south of the
Mogollon Rim with a tight moisture gradient and drier air to the
north. East or northeast steering flow off the higher terrain
would push afternoon storms into Gila County and the lower
elevations of Yavapai County provided the dry air doesn`t push too
far south and limit storm development on the Mogollon Rim - will
keep an eye on this. Far northern Arizona (along/north of Grand
Canyon to Window Rock) usually remains drier in this pattern. With
high pressure in place, expect hot temperatures in this area, 110+
at Phantom Ranch, 102-104 at Page and near 90 at Grand Canyon
.AVIATION...For the 18Z package...Expect another round of isolated
to scattered storms to develop this afternoon...most numerous from
KFLG east. VFR conditions will prevail but local MVFR and gusty
winds will be possible near any shower or storm. Aviation discussion
not updated for TAF amendments.
.FIRE WEATHER...Lingering monsoon moisture will keep isolated to
scattered thunderstorms in the forecast over the weekend. Storm
coverage is expected to be greatest over the White Mountains. Expect
hot temperatures and generally light winds.
Monday through Wednesday...Monsoon moisture remains over the region.
The daily chance for showers and thunderstorms will continue with an
increase in activity compared to the weekend.
.FGZ WATCHES/WARNINGS/ADVISORIES...Excessive Heat Warning until 7
PM MST this evening FOR AZZ006-037.
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