Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 06/25/16
Area Forecast Discussion
National Weather Service Phoenix AZ
835 PM MST FRI JUN 24 2016
.SYNOPSIS...
A very warm air mass will keep temperatures above normal through at
least the first half of next week. A gradual increase in moisture
will seep into portions of Arizona later this week and into next
week leading to a threat for showers and thunderstorms. Rainfall
will initially be limited to high terrain areas, then finally move
towards lower desert communities as we move into next week.
&&
.DISCUSSION...
Things have been a bit quieter this evening compared to yesterday,
when outflows from thunderstorms over se AZ pushed some dust into
south-central AZ. Convective activity this afternoon/evening has
developed further to the east, mainly south and east of Tucson
northeastward into the white mountains. This shift to the east,
combined with more westerly flow in the mid-levels of the
atmosphere, as indicated on the 00z Tucson balloon sounding, has
kept pretty much all outflow/convective activity out of our cwa.
Given current trends and latest high-res model forecasts, have
trimmed back pops across South-Central AZ and removed any mention of
blowing dust for our zones. Outside of these changes, and some minor
adjustments to the hourly temp/dewpoint/wind grids, current
forecasts are looking good, and no further updates are planned.
&&
.PREVIOUS DISCUSSION...
Rest of today through Monday...
Water vapor imagery indicates a vort max now over central AZ but
getting sheared out. It hasn`t been enough to produce much in the way
of convection. A larger short wave with an axis over southern CA is
moving in from the west. It is part of a much larger trough centered
over the Pacific northwest. Meanwhile and broad region of high
pressure is centered over the south-central CONUS but there is a
large inverted trough centered south of the Big Bend. Thus, flow
aloft with a westerly component is encountering flow aloft with an
easterly component over Arizona. Thus there is also a moisture
gradient over Arizona with decreasing values from east to west.
Isolated storms are now beginning to develop in southeast AZ where
destabilization from surface heating is getting underway. Anticipate
additional development there where CAPE is best. But with
southwesterly steering flow, storms will tend to move away from the
lower deserts of south-central AZ (including Phoenix). Outflow winds
are a possibility though. However, CAPE not looking good for those
lower deserts and thus outflows will struggle to produce new storms. Hi-
res models reflect this as well and keep deep convection pretty much
outside of our forecast area. But with a disturbance in the mix, and
proximity to southeast AZ, kept slight chance PoPs over portions of
Gila and Pinal counties for late this afternoon and evening.
Over the weekend, steering flow takes on an easterly component as
anticyclonic flow slowly builds over the the 4 corners. Deep moisture
doesn`t flood in but that is a better direction (climatologically) for
storms on the south-central AZ deserts. Thus PoPs subtly increase
from east to west. There are also indications of at least one
perturbation in the mix ahead of the large inverted trough which
stalls out near the Big Bend. Not much change in temps, though if
skies are clear and dew points decline, then highs will be a bit
warmer than forecast.
By Monday afternoon, the upper high is forecast to build to a 597dm
center located over far north central AZ near the Utah border. with
500mb heights in excess of 595dm over the central deserts, it will
turn even hotter, but the potential heat will be balanced by a
continued moisture feed from the east with pwat values climbing to
1.4 inches near the greater Phoenix area, and values over 1 inch
into southeast CA. Central desert surface dewpoints will rise into
the 50s and cloud cover will also increase from the east. As such
high temperatures will climb a degree or two with hottest western
deserts staying under 115, and most central deserts at or below 111.
With the increase in moisture and instability comes an increase in
CAPE and by Monday afternoon/evening we may see values in excess of
500 j/kg east of Phoenix. As such POPs have climbed a bit with
slight chances added to much of the south central deserts including
the greater Phoenix area, and POPs above 20 percent over southern
Gila County.
Tuesday through Thursday...Model guidance including NAEFS and GEFS
ensemble guidance is suggesting that our flow pattern is setting up
in a standard monsoonal fashion, with the upper high migrating
towards the vicinity of the four corners, and a much deeper and
widespread southeast steering flow working its way over the AZ
deserts and even into southeast CA. Moisture continues to work
across the lower deserts and rainfall chances will increase with
slight chances developing to the lower Colorado River valley and
potentially into the deserts of southeast CA. We have raised POPs
over much of the CWA correspondingly, with chance numbers over the
higher terrain of southern Gila County and slight chances over much
of the southcentral deserts westward. High temperatures take a slow
decline day to day as humidity values rise.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
Gusty erratic winds and blowing dust from distant SE AZ storms will
be possible this afternoon/ early evening , with a wind shift to the
south/southeast behind any outflows that make their way to Phoenix
terminals (after 23Z). However, low confidence in exact timing and
location precludes mention in 18Z TAF at this time. Outside of
potential storm outflows, winds will be out of the west with a few
gusts up to 20 kts before shifting to the east tomorrow morning. In
addition, skies will remain mostly clear with a few clouds aoa
10kft.
Southeast California/Southwest Arizona including KIPL and KBLH:
Mainly clear skies to prevail through the taf period. Winds to
remain mainly out of the south at KBLH, with sustained speeds as
high as 15 kts and a few gusts up to 20 kts possible during the late
afternoon/early evening hours. Winds at KIPL to mainly follow
typical diurnal trends with speeds around 10 to 15 kts.
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Monday through Friday...
Temperatures will start a gradual "cooling" trend, with highs on
Monday around 110-115F dropping into the 100-110F range by Friday.
Isolated thunderstorms are possible each afternoon/evening,
primarily over the higher terrain north and east of Phoenix on
Monday, and then over much of the desert southwest Tuesday through
Friday.
On Monday, given that conditions will remain dry in the lower levels
with minimum humidities generally between 10 and 20 percent, there
will be very little if any measurable rain. Mostly gusty erratic
winds and dry lightning will accompany storms potentially igniting
new fires or promoting the spread of existing fires.
Better chances for wetting rains is expected from Tuesday into
Friday as monsoon moisture levels increase over the region, with the
highest chances for rainfall still remaining over the higher terrain
of south-central AZ. Also accompanying the storms will be gusty
erratic winds and lightning. Minimum humidities during the Tuesday
through Friday period will rise into the 15-25 percent range, with
fair to good overnight recoveries.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
Visit us on Facebook...Twitter...and at weather.gov/phoenix
DISCUSSION...Percha/AJ/CB
AVIATION...Hernandez
FIRE WEATHER...Hernandez
[top]
Area Forecast Discussion
National Weather Service Flagstaff AZ
825 PM MST FRI JUN 24 2016
.SYNOPSIS...Expect mainly dry and warm conditions heading into the
weekend, with a few showers east of Flagstaff. Moisture will
return by early next week as a more monsoonal type of circulation
develops, leading to increased shower and thunderstorm activity
and more seasonable temperatures.
&&
.DISCUSSION...
Short-term forecast looks in good shape as light showers across
far eastern Arizona are winding down. Major updates to the
forecast are not anticipated this evening.
&&
.PREV DISCUSSION /301 PM MST/...Dry westerly flow in response to a
trough moving through the northern states will continue to
gradually push eastward today and tonight. Any shower and
thunderstorm activity will be confined to eastern Arizona,
primarily Apache County. The moisture plume will remain mostly
east of Arizona through the weekend with the exception of the
White Mountains and far eastern Arizona which will carry a chance
for thunderstorms. Daytime temperatures will be at least 5 degrees
warmer than average in most locations.
Models are in good agreement with high pressure establishing over
the four corners area by Sunday afternoon with an easterly flow
developing over Arizona. This will bring a healthy increase in
moisture resulting in daily showers and thunderstorms. The weather
next week will be more typical of monsoon season with daily
rainfall chances and closer to average temperatures. With the
general position of the high pressure not moving much through the
week, it`s likely this monsoonal circulation will continue through
the week.
&&
.AVIATION...For the 06Z Package...Isolated to scattered showers
and thunderstorms may redevelop east of a KPAN-KPGA line after 18Z
Saturday. Otherwise, expect VFR conditions. Smoke downwind of
area wildfires may impact visibility at times. Aviation discussion
not updated for TAF amendments.
&&
.FIRE WEATHER...Dry air will continue to move in from the west
over the next several days. This will limit shower and
thunderstorm coverage to the higher terrain in Apache county
through Saturday. These high based thunderstorms may produce
erratic gusty winds.
Monday through Wednesday...Additional moisture begins to move in
from the south and southeast with chances for showers and
thunderstorms expanding westward.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...KD/MCS
AVIATION...KD
FIRE WEATHER...MAS
For Northern Arizona weather information visit
weather.gov/flagstaff
Area Forecast Discussion
National Weather Service Flagstaff AZ
301 PM MST FRI JUN 24 2016
.SYNOPSIS...Expect mainly dry and warm conditions heading into the
weekend, with a few showers east of Flagstaff. Moisture will
return by early next week as a more monsoonal type of circulation
develops, leading to increased shower and thunderstorm activity
and more seasonable temperatures.
&&
.DISCUSSION...Dry westerly flow in response to a trough moving
through the northern states will continue to gradually push
eastward today and tonight. Any shower and thunderstorm activity
will be confined to eastern Arizona, primarily Apache County. The
moisture plume will remain mostly east of Arizona through the
weekend with the exception of the White Mountains and far eastern
Arizona which will carry a chance for thunderstorms. Daytime
temperatures will be at least 5 degrees warmer than average in
most locations.
Models are in good agreement with high pressure establishing over
the four corners area by Sunday afternoon with an easterly flow
developing over Arizona. This will bring a healthy increase in
moisture resulting in daily showers and thunderstorms. The
weather next week will be more typical of monsoon season with
daily rainfall chances and closer to average temperatures. With
the general position of the high pressure not moving much through
the week, it`s likely this monsoonal circulation will continue
through the week.
&&
.AVIATION...For the 00Z Package...ISOLD-SCT -SHRA/-TSRA G30-40kts
CIGS BKN040 east of a KPAN-KPGA line through 03Z...and again 18Z-
00Z Sat. Elsewhere, expect VFR conditions. Smoke downwind of area
wildfires may impact visibility at times. Aviation discussion not
updated for TAF amendments.
&&
.FIRE WEATHER...Dry air will continue to move in from the
west over the next several days. This will limit shower and
thunderstorm coverage to the higher terrain in Apache county through
Sunday. These high based thunderstorms may produce erratic gusty
winds.
Monday through Wednesday...Additional moisture begins to move in
from the south and southeast with chances for showers and
thunderstorms expanding westward.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...MCS
AVIATION...MAS
FIRE WEATHER...MAS
For Northern Arizona weather information visit
weather.gov/flagstaff
Area Forecast Discussion
National Weather Service Flagstaff AZ
301 PM MST FRI JUN 24 2016
.SYNOPSIS...Expect mainly dry and warm conditions heading into the
weekend, with a few showers east of Flagstaff. Moisture will
return by early next week as a more monsoonal type of circulation
develops, leading to increased shower and thunderstorm activity
and more seasonable temperatures.
&&
.DISCUSSION...Dry westerly flow in response to a trough moving
through the northern states will continue to gradually push
eastward today and tonight. Any shower and thunderstorm activity
will be confined to eastern Arizona, primarily Apache County. The
moisture plume will remain mostly east of Arizona through the
weekend with the exception of the White Mountains and far eastern
Arizona which will carry a chance for thunderstorms. Daytime
temperatures will be at least 5 degrees warmer than average in
most locations.
Models are in good agreement with high pressure establishing over
the four corners area by Sunday afternoon with an easterly flow
developing over Arizona. This will bring a healthy increase in
moisture resulting in daily showers and thunderstorms. The
weather next week will be more typical of monsoon season with
daily rainfall chances and closer to average temperatures. With
the general position of the high pressure not moving much through
the week, it`s likely this monsoonal circulation will continue
through the week.
&&
.AVIATION...For the 00Z Package...ISOLD-SCT -SHRA/-TSRA G30-40kts
CIGS BKN040 east of a KPAN-KPGA line through 03Z...and again 18Z-
00Z Sat. Elsewhere, expect VFR conditions. Smoke downwind of area
wildfires may impact visibility at times. Aviation discussion not
updated for TAF amendments.
&&
.FIRE WEATHER...Dry air will continue to move in from the
west over the next several days. This will limit shower and
thunderstorm coverage to the higher terrain in Apache county
through Saturday. These high based thunderstorms may produce
erratic gusty winds.
Monday through Wednesday...Additional moisture begins to move in
from the south and southeast with chances for showers and
thunderstorms expanding westward.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...MCS
AVIATION...MAS
FIRE WEATHER...MAS
For Northern Arizona weather information visit
weather.gov/flagstaff
Area Forecast Discussion
National Weather Service Phoenix AZ
254 PM MST FRI JUN 24 2016
.SYNOPSIS...
A very warm air mass will keep temperatures above normal through at
least the first half of next week. A gradual increase in moisture
will seep into portions of Arizona later this week and into next
week leading to a threat for showers and thunderstorms. Rainfall
will initially be limited to high terrain areas, then finally move
towards lower desert communities as we move into next week.
&&
.DISCUSSION...
Rest of today through Monday...
Water vapor imagery indicates a vort max now over central AZ but
getting sheared out. It hasn`t been enough to produce much in the way
of convection. A larger short wave with an axis over southern CA is
moving in from the west. It is part of a much larger trough centered
over the Pacific northwest. Meanwhile and broad region of high
pressure is centered over the south-central CONUS but there is a
large inverted trough centered south of the Big Bend. Thus, flow
aloft with a westerly component is encountering flow aloft with an
easterly component over Arizona. Thus there is also a moisture
gradient over Arizona with decreasing values from east to west.
Isolated storms are now beginning to develop in southeast AZ where
destabilization from surface heating is getting underway. Anticipate
additional development there where CAPE is best. But with
southwesterly steering flow, storms will tend to move away from the
lower deserts of south-central AZ (including Phoenix). Outflow winds
are a possibility though. However, CAPE not looking good for those
lower deserts and thus outflows will struggle to produce new storms. Hi-
res models reflect this as well and keep deep convection pretty much
outside of our forecast area. But with a disturbance in the mix, and
proximity to southeast AZ, kept slight chance PoPs over portions of
Gila and Pinal counties for late this afternoon and evening.
Over the weekend, steering flow takes on an easterly component as
anticyclonic flow slowly builds over the the 4 corners. Deep moisture
doesn`t flood in but that is a better direction (climatologically) for
storms on the south-central AZ deserts. Thus PoPs subtly increase
from east to west. There are also indications of at least one
perturbation in the mix ahead of the large inverted trough which
stalls out near the Big Bend. Not much change in temps, though if
skies are clear and dew points decline, then highs will be a bit
warmer than forecast.
By Monday afternoon, the upper high is forecast to build to a 597dm
center located over far north central AZ near the Utah border. with
500mb heights in excess of 595dm over the central deserts, it will
turn even hotter, but the potential heat will be balanced by a
continued moisture feed from the east with pwat values climbing to
1.4 inches near the greater Phoenix area, and values over 1 inch
into southeast CA. Central desert surface dewpoints will rise into
the 50s and cloud cover will also increase from the east. As such
high temperatures will climb a degree or two with hottest western
deserts staying under 115, and most central deserts at or below 111.
With the increase in moisture and instability comes an increase in
CAPE and by Monday afternoon/evening we may see values in excess of
500 j/kg east of Phoenix. As such POPs have climbed a bit with
slight chances added to much of the south central deserts including
the greater Phoenix area, and POPs above 20 percent over southern
Gila County.
Tuesday through Thursday...Model guidance including NAEFS and GEFS
ensemble guidance is suggesting that our flow pattern is setting up
in a standard monsoonal fashion, with the upper high migrating
towards the vicinity of the four corners, and a much deeper and
widespread southeast steering flow working its way over the AZ
deserts and even into southeast CA. Moisture continues to work
across the lower deserts and rainfall chances will increase with
slight chances developing to the lower Colorado River valley and
potentially into the deserts of southeast CA. We have raised POPs
over much of the CWA correspondingly, with chance numbers over the
higher terrain of southern Gila County and slight chances over much
of the southcentral deserts westward. High temperatures take a slow
decline day to day as humidity values rise.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
Gusty erratic winds and blowing dust from distant SE AZ storms will
be possible this afternoon/ early evening , with a wind shift to the
south/southeast behind any outflows that make their way to Phoenix
terminals (after 23Z). However, low confidence in exact timing and
location precludes mention in 18Z TAF at this time. Outside of
potential storm outflows, winds will be out of the west with a few
gusts up to 20 kts before shifting to the east tomorrow morning. In
addition, skies will remain mostly clear with a few clouds aoa
10kft.
Southeast California/Southwest Arizona including KIPL and KBLH:
Mainly clear skies to prevail through the taf period. Winds to
remain mainly out of the south at KBLH, with sustained speeds as
high as 15 kts and a few gusts up to 20 kts possible during the late
afternoon/early evening hours. Winds at KIPL to mainly follow
typical diurnal trends with speeds around 10 to 15 kts.
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Monday through Friday...
Temperatures will start a gradual "cooling" trend, with highs on
Monday around 110-115F dropping into the 100-110F range by Friday.
Isolated thunderstorms are possible each afternoon/evening,
primarily over the higher terrain north and east of Phoenix on
Monday, and then over much of the desert southwest Tuesday through
Friday.
On Monday, given that conditions will remain dry in the lower levels
with minimum humidities generally between 10 and 20 percent, there
will be very little if any measurable rain. Mostly gusty erratic
winds and dry lightning will accompany storms potentially igniting
new fires or promoting the spread of existing fires.
Better chances for wetting rains is expected from Tuesday into
Friday as monsoon moisture levels increase over the region, with the
highest chances for rainfall still remaining over the higher terrain
of south-central AZ. Also accompanying the storms will be gusty
erratic winds and lightning. Minimum humidities during the Tuesday
through Friday period will rise into the 15-25 percent range, with
fair to good overnight recoveries.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
Visit us on Facebook...Twitter...and at weather.gov/phoenix
DISCUSSION...AJ/CB
AVIATION...Hernandez
FIRE WEATHER...Hernandez
Area Forecast Discussion
National Weather Service Phoenix AZ
254 PM MST FRI JUN 24 2016
.SYNOPSIS...
A very warm air mass will keep temperatures above normal through at
least the first half of next week. A gradual increase in moisture
will seep into portions of Arizona later this week and into next
week leading to a threat for showers and thunderstorms. Rainfall
will initially be limited to high terrain areas, then finally move
towards lower desert communities as we move into next week.
&&
.DISCUSSION...
Rest of today through Monday...
Water vapor imagery indicates a vort max now over central AZ but
getting sheared out. It hasn`t been enough to produce much in the way
of convection. A larger short wave with an axis over southern CA is
moving in from the west. It is part of a much larger trough centered
over the Pacific northwest. Meanwhile and broad region of high
pressure is centered over the south-central CONUS but there is a
large inverted trough centered south of the Big Bend. Thus, flow
aloft with a westerly component is encountering flow aloft with an
easterly component over Arizona. Thus there is also a moisture
gradient over Arizona with decreasing values from east to west.
Isolated storms are now beginning to develop in southeast AZ where
destabilization from surface heating is getting underway. Anticipate
additional development there where CAPE is best. But with
southwesterly steering flow, storms will tend to move away from the
lower deserts of south-central AZ (including Phoenix). Outflow winds
are a possibility though. However, CAPE not looking good for those
lower deserts and thus outflows will struggle to produce new storms. Hi-
res models reflect this as well and keep deep convection pretty much
outside of our forecast area. But with a disturbance in the mix, and
proximity to southeast AZ, kept slight chance PoPs over portions of
Gila and Pinal counties for late this afternoon and evening.
Over the weekend, steering flow takes on an easterly component as
anticyclonic flow slowly builds over the the 4 corners. Deep moisture
doesn`t flood in but that is a better direction (climatologically) for
storms on the south-central AZ deserts. Thus PoPs subtly increase
from east to west. There are also indications of at least one
perturbation in the mix ahead of the large inverted trough which
stalls out near the Big Bend. Not much change in temps, though if
skies are clear and dew points decline, then highs will be a bit
warmer than forecast.
By Monday afternoon, the upper high is forecast to build to a 597dm
center located over far north central AZ near the Utah border. with
500mb heights in excess of 595dm over the central deserts, it will
turn even hotter, but the potential heat will be balanced by a
continued moisture feed from the east with pwat values climbing to
1.4 inches near the greater Phoenix area, and values over 1 inch
into southeast CA. Central desert surface dewpoints will rise into
the 50s and cloud cover will also increase from the east. As such
high temperatures will climb a degree or two with hottest western
deserts staying under 115, and most central deserts at or below 111.
With the increase in moisture and instability comes an increase in
CAPE and by Monday afternoon/evening we may see values in excess of
500 j/kg east of Phoenix. As such POPs have climbed a bit with
slight chances added to much of the south central deserts including
the greater Phoenix area, and POPs above 20 percent over southern
Gila County.
Tuesday through Thursday...Model guidance including NAEFS and GEFS
ensemble guidance is suggesting that our flow pattern is setting up
in a standard monsoonal fashion, with the upper high migrating
towards the vicinity of the four corners, and a much deeper and
widespread southeast steering flow working its way over the AZ
deserts and even into southeast CA. Moisture continues to work
across the lower deserts and rainfall chances will increase with
slight chances developing to the lower Colorado River valley and
potentially into the deserts of southeast CA. We have raised POPs
over much of the CWA correspondingly, with chance numbers over the
higher terrain of southern Gila County and slight chances over much
of the southcentral deserts westward. High temperatures take a slow
decline day to day as humidity values rise.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
Gusty erratic winds and blowing dust from distant SE AZ storms will
be possible this afternoon/ early evening , with a wind shift to the
south/southeast behind any outflows that make their way to Phoenix
terminals (after 23Z). However, low confidence in exact timing and
location precludes mention in 18Z TAF at this time. Outside of
potential storm outflows, winds will be out of the west with a few
gusts up to 20 kts before shifting to the east tomorrow morning. In
addition, skies will remain mostly clear with a few clouds aoa
10kft.
Southeast California/Southwest Arizona including KIPL and KBLH:
Mainly clear skies to prevail through the taf period. Winds to
remain mainly out of the south at KBLH, with sustained speeds as
high as 15 kts and a few gusts up to 20 kts possible during the late
afternoon/early evening hours. Winds at KIPL to mainly follow
typical diurnal trends with speeds around 10 to 15 kts.
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Monday through Friday...
Temperatures will start a gradual "cooling" trend, with highs on
Monday around 110-115F dropping into the 100-110F range by Friday.
Isolated thunderstorms are possible each afternoon/evening,
primarily over the higher terrain north and east of Phoenix on
Monday, and then over much of the desert southwest Tuesday through
Friday.
On Monday, given that conditions will remain dry in the lower levels
with minimum humidities generally between 10 and 20 percent, there
will be very little if any measurable rain. Mostly gusty erratic
winds and dry lightning will accompany storms potentially igniting
new fires or promoting the spread of existing fires.
Better chances for wetting rains is expected from Tuesday into
Friday as monsoon moisture levels increase over the region, with the
highest chances for rainfall still remaining over the higher terrain
of south-central AZ. Also accompanying the storms will be gusty
erratic winds and lightning. Minimum humidities during the Tuesday
through Friday period will rise into the 15-25 percent range, with
fair to good overnight recoveries.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
Visit us on Facebook...Twitter...and at weather.gov/phoenix
DISCUSSION...AJ/CB
AVIATION...Hernandez
FIRE WEATHER...Hernandez
[top]
Area Forecast Discussion
National Weather Service Tucson AZ
240 PM MST FRI JUN 24 2016
.SYNOPSIS...Adequate moisture will be around through the weekend into
next week for daily afternoon and evening showers and thunderstorms,
especially south and east of Tucson. Daytime high temperatures will
run near normal.
&&
.DISCUSSION...Scattered showers and thunderstorms were confined to
areas mainly east of a Tucson to Nogales line this afternoon. Alert
gages indicate rainfall amounts have generally remained less than a
third of an inch. Both the HRRR and the 24/12z UA-WRFNAM seem to be
handling this convection well. In addition, the last several runs of
the HRRR have depicted an outflow boundary originating from near
Tucson propagating northwest toward the Phoenix area between 24/23z
and 25/02z. As such, have included a mention of patchy blowing dust
in the forecast for a few hours this evening for portions of Pinal
County near I-10. At this point...expect convection to continue
across eastern zones into the evening and begin to diminish sometime
around or just after sunset.
Otherwise...the synoptic scale pattern was defined by longwave
ridging over much of the CONUS with low pressure moving into
northwestern Montana, as well as another disturbance pushing
northwestward along the Mexico/Texas border. Over the next several
days, it looks as though this Mexican low will stall before slowly
starting to move eastward through Texas, rather than move in our
direction. This will allow high pressure take hold of the desert
southwest early next week, with the center of high pressure setting
up near the favorable four corners region (for daily convection) by
Tuesday/Wednesday. Thereafter, high pressure seems to wobble around
the southwestern states a little bit, but overall remain in a good
position to ensure daily chances for monsoon activity. Showers and
storms this weekend will do well to moisten up the lower levels of
the atmosphere, so we will probably be looking at better coverage of
measurable precip and some higher QPF`s by the middle to end of
next week.
Bottom line is a general ramp up in shower and storm coverage
through the weekend which will persist into next week. The forecast
challenge will then shift to determining which days will be "up" or
"down" in terms of coverage and storm severity. Temperatures will
generally remain near normal though the forecast period.
&&
.AVIATION...VALID THRU 26/00Z.
Isold to sctd -TSRA/-SHRA thru 25/03z mainly E and S of KTUS. Sctd
debris cloud cover overnight with slgt chc of -SHRA. Isold -TSRA
dvlpg Sat after 25/19z mainly E and S of KTUS. Sfc wind until this
evening W-NW at 10-20 kts with gusts near 25 kts. Sfc wind will be
vrbl in direction at less than 10 kts at other times. Aviation
discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Isolated to scattered showers and thunderstorms will
occur across southeast Arizona through next Thursday. The best
chance of wetting rains during much of the period will be east-to-
south of Tucson. Daytime minimum relative humidity values will
generally range from the mid teens to around 30 percent with fair to
good nighttime recovery. 20-foot winds through Sunday as well as
next Wednesday and Thursday will generally be terrain driven at less
than 15 mph. 20-foot winds Monday and Tuesday will generally be from
the east at 5-15 mph with gusts of 20-25 mph. The strongest speeds
Monday and Tuesday should prevail from shortly after sunrise into
the early afternoon hours.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Discussion...French
Aviation/Fire Weather...Glueck
Area Forecast Discussion
National Weather Service Phoenix AZ
300 AM MST SAT JUN 25 2016
.SYNOPSIS...
A very warm air mass will keep temperatures above normal through at
least the first half of next week. A gradual increase in moisture
will seep into portions of Arizona later this week and into next
week leading to a threat for showers and thunderstorms. Rainfall
will initially be limited to high terrain areas, then finally move
towards lower desert communities as we move into next week.
&&
.DISCUSSION...
Early this morning, in the wake of troffing that passed by well to
our north, flow aloft over Arizona had turned to the west and
southwest as seen in the recent 00z AZ raobs as well as upper plot
data. Moisture, at least over eastern Arizona, remained a bit
elevated with a pwat of 1.16 inches at Tucson. Surface dewpoints
over the central deserts at 2 am were mostly in the 40s, values a
bit below typical monsoon thresholds. Latest IR imagery showed
partly cloudy skies east of Globe but west of southern Gila County
skies were clear.
Model guidance has not changed much over the past day or two and
still calls for just a very gradual import of moisture from the
southeast over the weekend, with most of the convective activity to
remain focused over higher terrain areas to the east and southeast
of Phoenix - mostly across southeast Arizona from Tucson east. A
weak inverted trof slowly creeps westward with time and steering flow
becomes weakly east/southeast with speeds around 5-10kt. Deeper
moisture stays east of Phoenix through Sunday evening and CAPE
values over the higher terrain of southern Gila County still appear
minimal, mostly below 300 j/kg. As such, POPs over the lower deserts
today and Sunday will mostly stay in the single digits with just
slight chances expected across the higher terrain east of Phoenix.
High temps will stay above seasonal normals, and actually will climb
a degree or two Sunday as high pressure aloft starts to strengthen
again. By Sunday, we should see highs in Phoenix reach around 111
with hotter western deserts climbing to around 113. Still, these
values will stay mostly near or just below heat warning thresholds
based on our heat impact level data. Once again, rain over the
deserts this weekend is a slim bet but there remains a somewhat
better chance for some blowing dust to work into portions of the
central deserts, mainly the southeast Phoenix metropolitan area and
portions of northern/northwest Pinal county such as Casa Grande and
the I-10 corridor southeast of Phoenix.
The idea of keeping convection and associated rainfall mainly over
higher terrain areas east/southeast of Phoenix this weekend is
supported by various mesocale models such as the WRK4KM and the
NMM6KM.
On Monday, progs agree that the upper high will continue to build to
our north and become centered near the Utah border over far
northcentral AZ, with a high center around 597DM. The orientation of
the high will allow for a much more monsoonal flow pattern to set up
with deeper easterly flow overspreading much of the lower deserts
and bringing pwat values over 1 inch into the far western deserts
and even into southeast CA. Still, the real deep lower level
moisture such as 850mb dewpoints over 10C remain east of Phoenix and
CAPE will still be minimal into the lower elevations. Due to the
more favorable steering flow and better moisture profile, we will
still call for slight chances of afternoon and evening thunderstorms
spreading into the south central deserts Monday, with chances
developing over the higher terrain east of Phoenix. With the very
warm air aloft, and the air over the western deserts still somewhat
on the dry side we can expect additional warming with high temps
reaching around 114 over the hotter western deserts Monday. Highs in
the Phoenix area will stay around 111. Overall, despite the warming
high temps will stay around but mostly a bit below excessive heat
warning thresholds Monday and we do not plan on issuing a heat watch
at this time.
Tuesday through Friday...Model guidance including NAEFS and GEFS
ensemble guidance continues to suggest that our flow pattern is
setting up in a standard monsoonal fashion, with the upper high
migrating towards the vicinity of the four corners, and a much
deeper and widespread southeast steering flow working its way over
the AZ deserts and even into southeast CA. Moisture continues to
work across the lower deserts and rainfall chances will increase
with slight chances developing to the lower Colorado River valley
and potentially into the deserts of southeast CA. We have raised
POPs over much of the CWA correspondingly, with chance numbers over
the higher terrain of southern Gila County and slight chances over
much of the southcentral deserts westward. High temperatures take a
slow decline day to day as humidity values rise.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
Weak sfc pressure gradients to keep winds on the light side, mainly
aob 10 kts through the taf period, mostly following typical diurnal
trends. Few-sct high cirrus cloud layers tonight and Sat morning to
give way to sct-bkn mid-high cloud layers on Sat aft/evening as
debris clouds from distant thunderstorms to the south and east
spread over the PHX area. There is also an outside chance that
outflows from these storms could affect one or more of the PHX area
terminals, with gusty winds and blowing dust, but confidence is too
low to include them in the tafs at this time.
Southeast California/Southwest Arizona including KIPL and KBLH:
Mainly clear skies to prevail through the taf period. Winds to
remain mainly out of the south at KBLH, with sustained speeds in the
7-10 kt range through Sat. Winds at KIPL to mainly follow typical
diurnal trends with speeds in the 7 to 10 kts range.
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Monday through Friday...
Temperatures will start a gradual "cooling" trend, with highs on
Monday around 110-115F dropping into the 100-110F range by Friday.
Isolated thunderstorms are possible each afternoon/evening,
primarily over the higher terrain north and east of Phoenix on
Monday, and then over much of the desert southwest Tuesday through
Friday.
On Monday, given that conditions will remain dry in the lower levels
with minimum humidities generally between 10 and 20 percent, there
will be very little if any measurable rain. Mostly gusty erratic
winds and dry lightning will accompany storms potentially igniting
new fires or promoting the spread of existing fires.
Better chances for wetting rains is expected from Tuesday into
Friday as monsoon moisture levels increase over the region, with the
highest chances for rainfall still remaining over the higher terrain
of south-central AZ. Also accompanying the storms will be gusty
erratic winds and lightning. Minimum humidities during the Tuesday
through Friday period will rise into the 15-25 percent range, with
fair to good overnight recoveries.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
Visit us on Facebook...Twitter...and at weather.gov/phoenix
DISCUSSION...CB
AVIATION...Percha
FIRE WEATHER...Hernandez
Area Forecast Discussion
National Weather Service Phoenix AZ
1020 PM MST FRI JUN 24 2016
.UPDATE...Updated Aviation Discussion...
.SYNOPSIS...
A very warm air mass will keep temperatures above normal through at
least the first half of next week. A gradual increase in moisture
will seep into portions of Arizona later this week and into next
week leading to a threat for showers and thunderstorms. Rainfall
will initially be limited to high terrain areas, then finally move
towards lower desert communities as we move into next week.
&&
.DISCUSSION...
Things have been a bit quieter this evening compared to yesterday,
when outflows from thunderstorms over se AZ pushed some dust into
south-central AZ. Convective activity this afternoon/evening has
developed further to the east, mainly south and east of Tucson
northeastward into the white mountains. This shift to the east,
combined with more westerly flow in the mid-levels of the
atmosphere, as indicated on the 00z Tucson balloon sounding, has
kept pretty much all outflow/convective activity out of our cwa.
Given current trends and latest high-res model forecasts, have
trimmed back pops across South-Central AZ and removed any mention of
blowing dust for our zones. Outside of these changes, and some minor
adjustments to the hourly temp/dewpoint/wind grids, current
forecasts are looking good, and no further updates are planned.
&&
.PREVIOUS DISCUSSION...
Rest of today through Monday...
Water vapor imagery indicates a vort max now over central AZ but
getting sheared out. It hasn`t been enough to produce much in the way
of convection. A larger short wave with an axis over southern CA is
moving in from the west. It is part of a much larger trough centered
over the Pacific northwest. Meanwhile and broad region of high
pressure is centered over the south-central CONUS but there is a
large inverted trough centered south of the Big Bend. Thus, flow
aloft with a westerly component is encountering flow aloft with an
easterly component over Arizona. Thus there is also a moisture
gradient over Arizona with decreasing values from east to west.
Isolated storms are now beginning to develop in southeast AZ where
destabilization from surface heating is getting underway. Anticipate
additional development there where CAPE is best. But with
southwesterly steering flow, storms will tend to move away from the
lower deserts of south-central AZ (including Phoenix). Outflow winds
are a possibility though. However, CAPE not looking good for those
lower deserts and thus outflows will struggle to produce new storms. Hi-
res models reflect this as well and keep deep convection pretty much
outside of our forecast area. But with a disturbance in the mix, and
proximity to southeast AZ, kept slight chance PoPs over portions of
Gila and Pinal counties for late this afternoon and evening.
Over the weekend, steering flow takes on an easterly component as
anticyclonic flow slowly builds over the the 4 corners. Deep moisture
doesn`t flood in but that is a better direction (climatologically) for
storms on the south-central AZ deserts. Thus PoPs subtly increase
from east to west. There are also indications of at least one
perturbation in the mix ahead of the large inverted trough which
stalls out near the Big Bend. Not much change in temps, though if
skies are clear and dew points decline, then highs will be a bit
warmer than forecast.
By Monday afternoon, the upper high is forecast to build to a 597dm
center located over far north central AZ near the Utah border. with
500mb heights in excess of 595dm over the central deserts, it will
turn even hotter, but the potential heat will be balanced by a
continued moisture feed from the east with pwat values climbing to
1.4 inches near the greater Phoenix area, and values over 1 inch
into southeast CA. Central desert surface dewpoints will rise into
the 50s and cloud cover will also increase from the east. As such
high temperatures will climb a degree or two with hottest western
deserts staying under 115, and most central deserts at or below 111.
With the increase in moisture and instability comes an increase in
CAPE and by Monday afternoon/evening we may see values in excess of
500 j/kg east of Phoenix. As such POPs have climbed a bit with
slight chances added to much of the south central deserts including
the greater Phoenix area, and POPs above 20 percent over southern
Gila County.
Tuesday through Thursday...Model guidance including NAEFS and GEFS
ensemble guidance is suggesting that our flow pattern is setting up
in a standard monsoonal fashion, with the upper high migrating
towards the vicinity of the four corners, and a much deeper and
widespread southeast steering flow working its way over the AZ
deserts and even into southeast CA. Moisture continues to work
across the lower deserts and rainfall chances will increase with
slight chances developing to the lower Colorado River valley and
potentially into the deserts of southeast CA. We have raised POPs
over much of the CWA correspondingly, with chance numbers over the
higher terrain of southern Gila County and slight chances over much
of the southcentral deserts westward. High temperatures take a slow
decline day to day as humidity values rise.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
Weak sfc pressure gradients to keep winds on the light side, mainly
aob 10 kts through the taf period, mostly following typical diurnal
trends. Few-sct high cirrus cloud layers tonight and Sat morning to
give way to sct-bkn mid-high cloud layers on Sat aft/evening as
debris clouds from distant thunderstorms to the south and east
spread over the PHX area. There is also an outside chance that
outflows from these storms could affect one or more of the PHX area
terminals, with gusty winds and blowing dust, but confidence is too
low to include them in the tafs at this time.
Southeast California/Southwest Arizona including KIPL and KBLH:
Mainly clear skies to prevail through the taf period. Winds to
remain mainly out of the south at KBLH, with sustained speeds in the
7-10 kt range through Sat. Winds at KIPL to mainly follow typical
diurnal trends with speeds in the 7 to 10 kts range.
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Monday through Friday...
Temperatures will start a gradual "cooling" trend, with highs on
Monday around 110-115F dropping into the 100-110F range by Friday.
Isolated thunderstorms are possible each afternoon/evening,
primarily over the higher terrain north and east of Phoenix on
Monday, and then over much of the desert southwest Tuesday through
Friday.
On Monday, given that conditions will remain dry in the lower levels
with minimum humidities generally between 10 and 20 percent, there
will be very little if any measurable rain. Mostly gusty erratic
winds and dry lightning will accompany storms potentially igniting
new fires or promoting the spread of existing fires.
Better chances for wetting rains is expected from Tuesday into
Friday as monsoon moisture levels increase over the region, with the
highest chances for rainfall still remaining over the higher terrain
of south-central AZ. Also accompanying the storms will be gusty
erratic winds and lightning. Minimum humidities during the Tuesday
through Friday period will rise into the 15-25 percent range, with
fair to good overnight recoveries.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
Visit us on Facebook...Twitter...and at weather.gov/phoenix
DISCUSSION...Percha/AJ/CB
AVIATION...Percha
FIRE WEATHER...Hernandez
Area Forecast Discussion
National Weather Service Phoenix AZ
1020 PM MST FRI JUN 24 2016
.UPDATE...Updated Aviation Discussion...
.SYNOPSIS...
A very warm air mass will keep temperatures above normal through at
least the first half of next week. A gradual increase in moisture
will seep into portions of Arizona later this week and into next
week leading to a threat for showers and thunderstorms. Rainfall
will initially be limited to high terrain areas, then finally move
towards lower desert communities as we move into next week.
&&
.DISCUSSION...
Things have been a bit quieter this evening compared to yesterday,
when outflows from thunderstorms over se AZ pushed some dust into
south-central AZ. Convective activity this afternoon/evening has
developed further to the east, mainly south and east of Tucson
northeastward into the white mountains. This shift to the east,
combined with more westerly flow in the mid-levels of the
atmosphere, as indicated on the 00z Tucson balloon sounding, has
kept pretty much all outflow/convective activity out of our cwa.
Given current trends and latest high-res model forecasts, have
trimmed back pops across South-Central AZ and removed any mention of
blowing dust for our zones. Outside of these changes, and some minor
adjustments to the hourly temp/dewpoint/wind grids, current
forecasts are looking good, and no further updates are planned.
&&
.PREVIOUS DISCUSSION...
Rest of today through Monday...
Water vapor imagery indicates a vort max now over central AZ but
getting sheared out. It hasn`t been enough to produce much in the way
of convection. A larger short wave with an axis over southern CA is
moving in from the west. It is part of a much larger trough centered
over the Pacific northwest. Meanwhile and broad region of high
pressure is centered over the south-central CONUS but there is a
large inverted trough centered south of the Big Bend. Thus, flow
aloft with a westerly component is encountering flow aloft with an
easterly component over Arizona. Thus there is also a moisture
gradient over Arizona with decreasing values from east to west.
Isolated storms are now beginning to develop in southeast AZ where
destabilization from surface heating is getting underway. Anticipate
additional development there where CAPE is best. But with
southwesterly steering flow, storms will tend to move away from the
lower deserts of south-central AZ (including Phoenix). Outflow winds
are a possibility though. However, CAPE not looking good for those
lower deserts and thus outflows will struggle to produce new storms. Hi-
res models reflect this as well and keep deep convection pretty much
outside of our forecast area. But with a disturbance in the mix, and
proximity to southeast AZ, kept slight chance PoPs over portions of
Gila and Pinal counties for late this afternoon and evening.
Over the weekend, steering flow takes on an easterly component as
anticyclonic flow slowly builds over the the 4 corners. Deep moisture
doesn`t flood in but that is a better direction (climatologically) for
storms on the south-central AZ deserts. Thus PoPs subtly increase
from east to west. There are also indications of at least one
perturbation in the mix ahead of the large inverted trough which
stalls out near the Big Bend. Not much change in temps, though if
skies are clear and dew points decline, then highs will be a bit
warmer than forecast.
By Monday afternoon, the upper high is forecast to build to a 597dm
center located over far north central AZ near the Utah border. with
500mb heights in excess of 595dm over the central deserts, it will
turn even hotter, but the potential heat will be balanced by a
continued moisture feed from the east with pwat values climbing to
1.4 inches near the greater Phoenix area, and values over 1 inch
into southeast CA. Central desert surface dewpoints will rise into
the 50s and cloud cover will also increase from the east. As such
high temperatures will climb a degree or two with hottest western
deserts staying under 115, and most central deserts at or below 111.
With the increase in moisture and instability comes an increase in
CAPE and by Monday afternoon/evening we may see values in excess of
500 j/kg east of Phoenix. As such POPs have climbed a bit with
slight chances added to much of the south central deserts including
the greater Phoenix area, and POPs above 20 percent over southern
Gila County.
Tuesday through Thursday...Model guidance including NAEFS and GEFS
ensemble guidance is suggesting that our flow pattern is setting up
in a standard monsoonal fashion, with the upper high migrating
towards the vicinity of the four corners, and a much deeper and
widespread southeast steering flow working its way over the AZ
deserts and even into southeast CA. Moisture continues to work
across the lower deserts and rainfall chances will increase with
slight chances developing to the lower Colorado River valley and
potentially into the deserts of southeast CA. We have raised POPs
over much of the CWA correspondingly, with chance numbers over the
higher terrain of southern Gila County and slight chances over much
of the southcentral deserts westward. High temperatures take a slow
decline day to day as humidity values rise.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
Weak sfc pressure gradients to keep winds on the light side, mainly
aob 10 kts through the taf period, mostly following typical diurnal
trends. Few-sct high cirrus cloud layers tonight and Sat morning to
give way to sct-bkn mid-high cloud layers on Sat aft/evening as
debris clouds from distant thunderstorms to the south and east
spread over the PHX area. There is also an outside chance that
outflows from these storms could affect one or more of the PHX area
terminals, with gusty winds and blowing dust, but confidence is too
low to include them in the tafs at this time.
Southeast California/Southwest Arizona including KIPL and KBLH:
Mainly clear skies to prevail through the taf period. Winds to
remain mainly out of the south at KBLH, with sustained speeds in the
7-10 kt range through Sat. Winds at KIPL to mainly follow typical
diurnal trends with speeds in the 7 to 10 kts range.
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Monday through Friday...
Temperatures will start a gradual "cooling" trend, with highs on
Monday around 110-115F dropping into the 100-110F range by Friday.
Isolated thunderstorms are possible each afternoon/evening,
primarily over the higher terrain north and east of Phoenix on
Monday, and then over much of the desert southwest Tuesday through
Friday.
On Monday, given that conditions will remain dry in the lower levels
with minimum humidities generally between 10 and 20 percent, there
will be very little if any measurable rain. Mostly gusty erratic
winds and dry lightning will accompany storms potentially igniting
new fires or promoting the spread of existing fires.
Better chances for wetting rains is expected from Tuesday into
Friday as monsoon moisture levels increase over the region, with the
highest chances for rainfall still remaining over the higher terrain
of south-central AZ. Also accompanying the storms will be gusty
erratic winds and lightning. Minimum humidities during the Tuesday
through Friday period will rise into the 15-25 percent range, with
fair to good overnight recoveries.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
Visit us on Facebook...Twitter...and at weather.gov/phoenix
DISCUSSION...Percha/AJ/CB
AVIATION...Percha
FIRE WEATHER...Hernandez
[top]
Area Forecast Discussion
National Weather Service Tucson AZ
910 PM MST FRI JUN 24 2016
.SYNOPSIS...Adequate moisture will be around through the weekend into
next week for daily afternoon and evening showers and thunderstorms,
especially south and east of Tucson. Daytime high temperatures will
run near normal.
&&
.DISCUSSION...Water vapor imagery shows high pressure aloft centered
over the lower Mississippi river valley with the associated ridge
axis extending across Texas toward New Mexico. Meanwhile, a weak
shortwave trough axis resides across Arizona with a very distinct
demarcation between dry air to our west and moist air to our east on
the western flank of the ridge, but also ahead of a low over
northeast Mexico. Between these systems lies a deformation zone over
parts of Sonora and Chihuahua Mexico. IR satellite imagery from
earlier today shows convection that blossomed over the Sierra Madre
Occidentals of Mexico, with a large swath of cloudiness and
convection over much of northern Mexico, eastern Arizona and western
two-thirds of New Mexico.
Convection developed relatively early today at around noon, mainly
between Tucson and Nogales and into parts of Cochise county.
Rainfall amounts were light, generally under a tenth of an inch,
with some isolated amounts of around a third to near a half. The
winner with respect to rainfall was the Long Park gauge in the
Chiricahua mountains of east central Cochise county where 0.75
inches fell.
Current satellite and radar trends are indicating that the cloud
tops over northern Mexico have been warming and most of the showers
over my forecast area have dissipated. Still some activity south of
the border and in southwest New Mexico, but the trend is for the
showers to gradually dissipate through the remainder of the evening
and into the overnight hours. Will make some adjustments to the POP
grids for the remainder of tonight. Will leave in some slight
chances near the international border and our border with New Mexico
in case outflows from the south and east trigger additional activity
later on tonight. Elsewhere, not much if any, precipitation is
expected for the rest of tonight.
As of 03Z (8 PM MST), temperatures ranged from the mid 70s to the
mid 90s, with the Tucson intl airport reporting a temp of 92 degs,
after reaching an afternoon high of 103 degs. Will make some
adjustments to the short term hourly temperature grids to reflect
the most recent trends, but inherited overnight low temps seem to be
fine.
For details beyond tonight, please refer to the previous discussion
below.
&&
.AVIATION...VALID THRU 26/06Z.
Isold -SHRA possible overnight, mainly near the border with Mexico
and New Mexico. Debris clouds will continue to cover the eastern
half of the forecast area overnight, but will slowly erode through
sunrise Saturday. Isold -TSRA dvlpg Sat after 25/19Z mainly E and S
of KTUS. Sfc wind will be vrbl in direction at less than 10 kts
overnight, but expect generally west to northwest flow at 15 kts or
less during the afternoon on Saturday. Winds potentially strong and
gusty near thunderstorms. Aviation discussion not updated for TAF
amendments.
&&
.FIRE WEATHER...Isolated to scattered showers and thunderstorms will
occur across southeast Arizona through next Thursday. The best
chance of wetting rains during much of the period will be east-to-
south of Tucson. Daytime minimum relative humidity values will
generally range from the mid teens to around 30 percent with fair to
good nighttime recovery. 20-foot winds through Sunday as well as
next Wednesday and Thursday will generally be terrain driven at less
than 15 mph. 20-foot winds Monday and Tuesday will generally be from
the east at 5-15 mph with gusts of 20-25 mph. The strongest speeds
Monday and Tuesday should prevail from shortly after sunrise into
the early afternoon hours.
&&
.PREV DISCUSSION...The synoptic scale pattern was defined by
longwave ridging over much of the CONUS with low pressure moving
into northwestern Montana, as well as another disturbance pushing
northwestward along the Mexico/Texas border. Over the next several
days, it looks as though this Mexican low will stall before slowly
starting to move eastward through Texas, rather than move in our
direction. This will allow high pressure take hold of the desert
southwest early next week, with the center of high pressure setting
up near the favorable four corners region (for daily convection) by
Tuesday/Wednesday. Thereafter, high pressure seems to wobble around
the southwestern states a little bit, but overall remain in a good
position to ensure daily chances for monsoon activity. Showers and
storms this weekend will do well to moisten up the lower levels of
the atmosphere, so we will probably be looking at better coverage of
measurable precip and some higher QPF`s by the middle to end of next
week.
Bottom line is a general ramp up in shower and storm coverage
through the weekend which will persist into next week. The forecast
challenge will then shift to determining which days will be "up" or
"down" in terms of coverage and storm severity. Temperatures will
generally remain near normal though the forecast period.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
DISCUSSION...Mollere
PREVIOUS DISCUSSION...French
AVIATION/FIRE WEATHER...Mollere/Glueck
Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Area Forecast Discussion
National Weather Service Phoenix AZ
835 PM MST FRI JUN 24 2016
.SYNOPSIS...
A very warm air mass will keep temperatures above normal through at
least the first half of next week. A gradual increase in moisture
will seep into portions of Arizona later this week and into next
week leading to a threat for showers and thunderstorms. Rainfall
will initially be limited to high terrain areas, then finally move
towards lower desert communities as we move into next week.
&&
.DISCUSSION...
Things have been a bit quieter this evening compared to yesterday,
when outflows from thunderstorms over se AZ pushed some dust into
south-central AZ. Convective activity this afternoon/evening has
developed further to the east, mainly south and east of Tucson
northeastward into the white mountains. This shift to the east,
combined with more westerly flow in the mid-levels of the
atmosphere, as indicated on the 00z Tucson balloon sounding, has
kept pretty much all outflow/convective activity out of our cwa.
Given current trends and latest high-res model forecasts, have
trimmed back pops across South-Central AZ and removed any mention of
blowing dust for our zones. Outside of these changes, and some minor
adjustments to the hourly temp/dewpoint/wind grids, current
forecasts are looking good, and no further updates are planned.
&&
.PREVIOUS DISCUSSION...
Rest of today through Monday...
Water vapor imagery indicates a vort max now over central AZ but
getting sheared out. It hasn`t been enough to produce much in the way
of convection. A larger short wave with an axis over southern CA is
moving in from the west. It is part of a much larger trough centered
over the Pacific northwest. Meanwhile and broad region of high
pressure is centered over the south-central CONUS but there is a
large inverted trough centered south of the Big Bend. Thus, flow
aloft with a westerly component is encountering flow aloft with an
easterly component over Arizona. Thus there is also a moisture
gradient over Arizona with decreasing values from east to west.
Isolated storms are now beginning to develop in southeast AZ where
destabilization from surface heating is getting underway. Anticipate
additional development there where CAPE is best. But with
southwesterly steering flow, storms will tend to move away from the
lower deserts of south-central AZ (including Phoenix). Outflow winds
are a possibility though. However, CAPE not looking good for those
lower deserts and thus outflows will struggle to produce new storms. Hi-
res models reflect this as well and keep deep convection pretty much
outside of our forecast area. But with a disturbance in the mix, and
proximity to southeast AZ, kept slight chance PoPs over portions of
Gila and Pinal counties for late this afternoon and evening.
Over the weekend, steering flow takes on an easterly component as
anticyclonic flow slowly builds over the the 4 corners. Deep moisture
doesn`t flood in but that is a better direction (climatologically) for
storms on the south-central AZ deserts. Thus PoPs subtly increase
from east to west. There are also indications of at least one
perturbation in the mix ahead of the large inverted trough which
stalls out near the Big Bend. Not much change in temps, though if
skies are clear and dew points decline, then highs will be a bit
warmer than forecast.
By Monday afternoon, the upper high is forecast to build to a 597dm
center located over far north central AZ near the Utah border. with
500mb heights in excess of 595dm over the central deserts, it will
turn even hotter, but the potential heat will be balanced by a
continued moisture feed from the east with pwat values climbing to
1.4 inches near the greater Phoenix area, and values over 1 inch
into southeast CA. Central desert surface dewpoints will rise into
the 50s and cloud cover will also increase from the east. As such
high temperatures will climb a degree or two with hottest western
deserts staying under 115, and most central deserts at or below 111.
With the increase in moisture and instability comes an increase in
CAPE and by Monday afternoon/evening we may see values in excess of
500 j/kg east of Phoenix. As such POPs have climbed a bit with
slight chances added to much of the south central deserts including
the greater Phoenix area, and POPs above 20 percent over southern
Gila County.
Tuesday through Thursday...Model guidance including NAEFS and GEFS
ensemble guidance is suggesting that our flow pattern is setting up
in a standard monsoonal fashion, with the upper high migrating
towards the vicinity of the four corners, and a much deeper and
widespread southeast steering flow working its way over the AZ
deserts and even into southeast CA. Moisture continues to work
across the lower deserts and rainfall chances will increase with
slight chances developing to the lower Colorado River valley and
potentially into the deserts of southeast CA. We have raised POPs
over much of the CWA correspondingly, with chance numbers over the
higher terrain of southern Gila County and slight chances over much
of the southcentral deserts westward. High temperatures take a slow
decline day to day as humidity values rise.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
Gusty erratic winds and blowing dust from distant SE AZ storms will
be possible this afternoon/ early evening , with a wind shift to the
south/southeast behind any outflows that make their way to Phoenix
terminals (after 23Z). However, low confidence in exact timing and
location precludes mention in 18Z TAF at this time. Outside of
potential storm outflows, winds will be out of the west with a few
gusts up to 20 kts before shifting to the east tomorrow morning. In
addition, skies will remain mostly clear with a few clouds aoa
10kft.
Southeast California/Southwest Arizona including KIPL and KBLH:
Mainly clear skies to prevail through the taf period. Winds to
remain mainly out of the south at KBLH, with sustained speeds as
high as 15 kts and a few gusts up to 20 kts possible during the late
afternoon/early evening hours. Winds at KIPL to mainly follow
typical diurnal trends with speeds around 10 to 15 kts.
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Monday through Friday...
Temperatures will start a gradual "cooling" trend, with highs on
Monday around 110-115F dropping into the 100-110F range by Friday.
Isolated thunderstorms are possible each afternoon/evening,
primarily over the higher terrain north and east of Phoenix on
Monday, and then over much of the desert southwest Tuesday through
Friday.
On Monday, given that conditions will remain dry in the lower levels
with minimum humidities generally between 10 and 20 percent, there
will be very little if any measurable rain. Mostly gusty erratic
winds and dry lightning will accompany storms potentially igniting
new fires or promoting the spread of existing fires.
Better chances for wetting rains is expected from Tuesday into
Friday as monsoon moisture levels increase over the region, with the
highest chances for rainfall still remaining over the higher terrain
of south-central AZ. Also accompanying the storms will be gusty
erratic winds and lightning. Minimum humidities during the Tuesday
through Friday period will rise into the 15-25 percent range, with
fair to good overnight recoveries.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
Visit us on Facebook...Twitter...and at weather.gov/phoenix
DISCUSSION...Percha/AJ/CB
AVIATION...Hernandez
FIRE WEATHER...Hernandez
[top]
Area Forecast Discussion
National Weather Service Flagstaff AZ
825 PM MST FRI JUN 24 2016
.SYNOPSIS...Expect mainly dry and warm conditions heading into the
weekend, with a few showers east of Flagstaff. Moisture will
return by early next week as a more monsoonal type of circulation
develops, leading to increased shower and thunderstorm activity
and more seasonable temperatures.
&&
.DISCUSSION...
Short-term forecast looks in good shape as light showers across
far eastern Arizona are winding down. Major updates to the
forecast are not anticipated this evening.
&&
.PREV DISCUSSION /301 PM MST/...Dry westerly flow in response to a
trough moving through the northern states will continue to
gradually push eastward today and tonight. Any shower and
thunderstorm activity will be confined to eastern Arizona,
primarily Apache County. The moisture plume will remain mostly
east of Arizona through the weekend with the exception of the
White Mountains and far eastern Arizona which will carry a chance
for thunderstorms. Daytime temperatures will be at least 5 degrees
warmer than average in most locations.
Models are in good agreement with high pressure establishing over
the four corners area by Sunday afternoon with an easterly flow
developing over Arizona. This will bring a healthy increase in
moisture resulting in daily showers and thunderstorms. The weather
next week will be more typical of monsoon season with daily
rainfall chances and closer to average temperatures. With the
general position of the high pressure not moving much through the
week, it`s likely this monsoonal circulation will continue through
the week.
&&
.AVIATION...For the 06Z Package...Isolated to scattered showers
and thunderstorms may redevelop east of a KPAN-KPGA line after 18Z
Saturday. Otherwise, expect VFR conditions. Smoke downwind of
area wildfires may impact visibility at times. Aviation discussion
not updated for TAF amendments.
&&
.FIRE WEATHER...Dry air will continue to move in from the west
over the next several days. This will limit shower and
thunderstorm coverage to the higher terrain in Apache county
through Saturday. These high based thunderstorms may produce
erratic gusty winds.
Monday through Wednesday...Additional moisture begins to move in
from the south and southeast with chances for showers and
thunderstorms expanding westward.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...KD/MCS
AVIATION...KD
FIRE WEATHER...MAS
For Northern Arizona weather information visit
weather.gov/flagstaff
Area Forecast Discussion
National Weather Service Flagstaff AZ
301 PM MST FRI JUN 24 2016
.SYNOPSIS...Expect mainly dry and warm conditions heading into the
weekend, with a few showers east of Flagstaff. Moisture will
return by early next week as a more monsoonal type of circulation
develops, leading to increased shower and thunderstorm activity
and more seasonable temperatures.
&&
.DISCUSSION...Dry westerly flow in response to a trough moving
through the northern states will continue to gradually push
eastward today and tonight. Any shower and thunderstorm activity
will be confined to eastern Arizona, primarily Apache County. The
moisture plume will remain mostly east of Arizona through the
weekend with the exception of the White Mountains and far eastern
Arizona which will carry a chance for thunderstorms. Daytime
temperatures will be at least 5 degrees warmer than average in
most locations.
Models are in good agreement with high pressure establishing over
the four corners area by Sunday afternoon with an easterly flow
developing over Arizona. This will bring a healthy increase in
moisture resulting in daily showers and thunderstorms. The
weather next week will be more typical of monsoon season with
daily rainfall chances and closer to average temperatures. With
the general position of the high pressure not moving much through
the week, it`s likely this monsoonal circulation will continue
through the week.
&&
.AVIATION...For the 00Z Package...ISOLD-SCT -SHRA/-TSRA G30-40kts
CIGS BKN040 east of a KPAN-KPGA line through 03Z...and again 18Z-
00Z Sat. Elsewhere, expect VFR conditions. Smoke downwind of area
wildfires may impact visibility at times. Aviation discussion not
updated for TAF amendments.
&&
.FIRE WEATHER...Dry air will continue to move in from the
west over the next several days. This will limit shower and
thunderstorm coverage to the higher terrain in Apache county through
Sunday. These high based thunderstorms may produce erratic gusty
winds.
Monday through Wednesday...Additional moisture begins to move in
from the south and southeast with chances for showers and
thunderstorms expanding westward.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...MCS
AVIATION...MAS
FIRE WEATHER...MAS
For Northern Arizona weather information visit
weather.gov/flagstaff
Area Forecast Discussion
National Weather Service Flagstaff AZ
301 PM MST FRI JUN 24 2016
.SYNOPSIS...Expect mainly dry and warm conditions heading into the
weekend, with a few showers east of Flagstaff. Moisture will
return by early next week as a more monsoonal type of circulation
develops, leading to increased shower and thunderstorm activity
and more seasonable temperatures.
&&
.DISCUSSION...Dry westerly flow in response to a trough moving
through the northern states will continue to gradually push
eastward today and tonight. Any shower and thunderstorm activity
will be confined to eastern Arizona, primarily Apache County. The
moisture plume will remain mostly east of Arizona through the
weekend with the exception of the White Mountains and far eastern
Arizona which will carry a chance for thunderstorms. Daytime
temperatures will be at least 5 degrees warmer than average in
most locations.
Models are in good agreement with high pressure establishing over
the four corners area by Sunday afternoon with an easterly flow
developing over Arizona. This will bring a healthy increase in
moisture resulting in daily showers and thunderstorms. The
weather next week will be more typical of monsoon season with
daily rainfall chances and closer to average temperatures. With
the general position of the high pressure not moving much through
the week, it`s likely this monsoonal circulation will continue
through the week.
&&
.AVIATION...For the 00Z Package...ISOLD-SCT -SHRA/-TSRA G30-40kts
CIGS BKN040 east of a KPAN-KPGA line through 03Z...and again 18Z-
00Z Sat. Elsewhere, expect VFR conditions. Smoke downwind of area
wildfires may impact visibility at times. Aviation discussion not
updated for TAF amendments.
&&
.FIRE WEATHER...Dry air will continue to move in from the
west over the next several days. This will limit shower and
thunderstorm coverage to the higher terrain in Apache county
through Saturday. These high based thunderstorms may produce
erratic gusty winds.
Monday through Wednesday...Additional moisture begins to move in
from the south and southeast with chances for showers and
thunderstorms expanding westward.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...MCS
AVIATION...MAS
FIRE WEATHER...MAS
For Northern Arizona weather information visit
weather.gov/flagstaff
Area Forecast Discussion
National Weather Service Phoenix AZ
254 PM MST FRI JUN 24 2016
.SYNOPSIS...
A very warm air mass will keep temperatures above normal through at
least the first half of next week. A gradual increase in moisture
will seep into portions of Arizona later this week and into next
week leading to a threat for showers and thunderstorms. Rainfall
will initially be limited to high terrain areas, then finally move
towards lower desert communities as we move into next week.
&&
.DISCUSSION...
Rest of today through Monday...
Water vapor imagery indicates a vort max now over central AZ but
getting sheared out. It hasn`t been enough to produce much in the way
of convection. A larger short wave with an axis over southern CA is
moving in from the west. It is part of a much larger trough centered
over the Pacific northwest. Meanwhile and broad region of high
pressure is centered over the south-central CONUS but there is a
large inverted trough centered south of the Big Bend. Thus, flow
aloft with a westerly component is encountering flow aloft with an
easterly component over Arizona. Thus there is also a moisture
gradient over Arizona with decreasing values from east to west.
Isolated storms are now beginning to develop in southeast AZ where
destabilization from surface heating is getting underway. Anticipate
additional development there where CAPE is best. But with
southwesterly steering flow, storms will tend to move away from the
lower deserts of south-central AZ (including Phoenix). Outflow winds
are a possibility though. However, CAPE not looking good for those
lower deserts and thus outflows will struggle to produce new storms. Hi-
res models reflect this as well and keep deep convection pretty much
outside of our forecast area. But with a disturbance in the mix, and
proximity to southeast AZ, kept slight chance PoPs over portions of
Gila and Pinal counties for late this afternoon and evening.
Over the weekend, steering flow takes on an easterly component as
anticyclonic flow slowly builds over the the 4 corners. Deep moisture
doesn`t flood in but that is a better direction (climatologically) for
storms on the south-central AZ deserts. Thus PoPs subtly increase
from east to west. There are also indications of at least one
perturbation in the mix ahead of the large inverted trough which
stalls out near the Big Bend. Not much change in temps, though if
skies are clear and dew points decline, then highs will be a bit
warmer than forecast.
By Monday afternoon, the upper high is forecast to build to a 597dm
center located over far north central AZ near the Utah border. with
500mb heights in excess of 595dm over the central deserts, it will
turn even hotter, but the potential heat will be balanced by a
continued moisture feed from the east with pwat values climbing to
1.4 inches near the greater Phoenix area, and values over 1 inch
into southeast CA. Central desert surface dewpoints will rise into
the 50s and cloud cover will also increase from the east. As such
high temperatures will climb a degree or two with hottest western
deserts staying under 115, and most central deserts at or below 111.
With the increase in moisture and instability comes an increase in
CAPE and by Monday afternoon/evening we may see values in excess of
500 j/kg east of Phoenix. As such POPs have climbed a bit with
slight chances added to much of the south central deserts including
the greater Phoenix area, and POPs above 20 percent over southern
Gila County.
Tuesday through Thursday...Model guidance including NAEFS and GEFS
ensemble guidance is suggesting that our flow pattern is setting up
in a standard monsoonal fashion, with the upper high migrating
towards the vicinity of the four corners, and a much deeper and
widespread southeast steering flow working its way over the AZ
deserts and even into southeast CA. Moisture continues to work
across the lower deserts and rainfall chances will increase with
slight chances developing to the lower Colorado River valley and
potentially into the deserts of southeast CA. We have raised POPs
over much of the CWA correspondingly, with chance numbers over the
higher terrain of southern Gila County and slight chances over much
of the southcentral deserts westward. High temperatures take a slow
decline day to day as humidity values rise.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
Gusty erratic winds and blowing dust from distant SE AZ storms will
be possible this afternoon/ early evening , with a wind shift to the
south/southeast behind any outflows that make their way to Phoenix
terminals (after 23Z). However, low confidence in exact timing and
location precludes mention in 18Z TAF at this time. Outside of
potential storm outflows, winds will be out of the west with a few
gusts up to 20 kts before shifting to the east tomorrow morning. In
addition, skies will remain mostly clear with a few clouds aoa
10kft.
Southeast California/Southwest Arizona including KIPL and KBLH:
Mainly clear skies to prevail through the taf period. Winds to
remain mainly out of the south at KBLH, with sustained speeds as
high as 15 kts and a few gusts up to 20 kts possible during the late
afternoon/early evening hours. Winds at KIPL to mainly follow
typical diurnal trends with speeds around 10 to 15 kts.
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Monday through Friday...
Temperatures will start a gradual "cooling" trend, with highs on
Monday around 110-115F dropping into the 100-110F range by Friday.
Isolated thunderstorms are possible each afternoon/evening,
primarily over the higher terrain north and east of Phoenix on
Monday, and then over much of the desert southwest Tuesday through
Friday.
On Monday, given that conditions will remain dry in the lower levels
with minimum humidities generally between 10 and 20 percent, there
will be very little if any measurable rain. Mostly gusty erratic
winds and dry lightning will accompany storms potentially igniting
new fires or promoting the spread of existing fires.
Better chances for wetting rains is expected from Tuesday into
Friday as monsoon moisture levels increase over the region, with the
highest chances for rainfall still remaining over the higher terrain
of south-central AZ. Also accompanying the storms will be gusty
erratic winds and lightning. Minimum humidities during the Tuesday
through Friday period will rise into the 15-25 percent range, with
fair to good overnight recoveries.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
Visit us on Facebook...Twitter...and at weather.gov/phoenix
DISCUSSION...AJ/CB
AVIATION...Hernandez
FIRE WEATHER...Hernandez
Area Forecast Discussion
National Weather Service Phoenix AZ
254 PM MST FRI JUN 24 2016
.SYNOPSIS...
A very warm air mass will keep temperatures above normal through at
least the first half of next week. A gradual increase in moisture
will seep into portions of Arizona later this week and into next
week leading to a threat for showers and thunderstorms. Rainfall
will initially be limited to high terrain areas, then finally move
towards lower desert communities as we move into next week.
&&
.DISCUSSION...
Rest of today through Monday...
Water vapor imagery indicates a vort max now over central AZ but
getting sheared out. It hasn`t been enough to produce much in the way
of convection. A larger short wave with an axis over southern CA is
moving in from the west. It is part of a much larger trough centered
over the Pacific northwest. Meanwhile and broad region of high
pressure is centered over the south-central CONUS but there is a
large inverted trough centered south of the Big Bend. Thus, flow
aloft with a westerly component is encountering flow aloft with an
easterly component over Arizona. Thus there is also a moisture
gradient over Arizona with decreasing values from east to west.
Isolated storms are now beginning to develop in southeast AZ where
destabilization from surface heating is getting underway. Anticipate
additional development there where CAPE is best. But with
southwesterly steering flow, storms will tend to move away from the
lower deserts of south-central AZ (including Phoenix). Outflow winds
are a possibility though. However, CAPE not looking good for those
lower deserts and thus outflows will struggle to produce new storms. Hi-
res models reflect this as well and keep deep convection pretty much
outside of our forecast area. But with a disturbance in the mix, and
proximity to southeast AZ, kept slight chance PoPs over portions of
Gila and Pinal counties for late this afternoon and evening.
Over the weekend, steering flow takes on an easterly component as
anticyclonic flow slowly builds over the the 4 corners. Deep moisture
doesn`t flood in but that is a better direction (climatologically) for
storms on the south-central AZ deserts. Thus PoPs subtly increase
from east to west. There are also indications of at least one
perturbation in the mix ahead of the large inverted trough which
stalls out near the Big Bend. Not much change in temps, though if
skies are clear and dew points decline, then highs will be a bit
warmer than forecast.
By Monday afternoon, the upper high is forecast to build to a 597dm
center located over far north central AZ near the Utah border. with
500mb heights in excess of 595dm over the central deserts, it will
turn even hotter, but the potential heat will be balanced by a
continued moisture feed from the east with pwat values climbing to
1.4 inches near the greater Phoenix area, and values over 1 inch
into southeast CA. Central desert surface dewpoints will rise into
the 50s and cloud cover will also increase from the east. As such
high temperatures will climb a degree or two with hottest western
deserts staying under 115, and most central deserts at or below 111.
With the increase in moisture and instability comes an increase in
CAPE and by Monday afternoon/evening we may see values in excess of
500 j/kg east of Phoenix. As such POPs have climbed a bit with
slight chances added to much of the south central deserts including
the greater Phoenix area, and POPs above 20 percent over southern
Gila County.
Tuesday through Thursday...Model guidance including NAEFS and GEFS
ensemble guidance is suggesting that our flow pattern is setting up
in a standard monsoonal fashion, with the upper high migrating
towards the vicinity of the four corners, and a much deeper and
widespread southeast steering flow working its way over the AZ
deserts and even into southeast CA. Moisture continues to work
across the lower deserts and rainfall chances will increase with
slight chances developing to the lower Colorado River valley and
potentially into the deserts of southeast CA. We have raised POPs
over much of the CWA correspondingly, with chance numbers over the
higher terrain of southern Gila County and slight chances over much
of the southcentral deserts westward. High temperatures take a slow
decline day to day as humidity values rise.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
Gusty erratic winds and blowing dust from distant SE AZ storms will
be possible this afternoon/ early evening , with a wind shift to the
south/southeast behind any outflows that make their way to Phoenix
terminals (after 23Z). However, low confidence in exact timing and
location precludes mention in 18Z TAF at this time. Outside of
potential storm outflows, winds will be out of the west with a few
gusts up to 20 kts before shifting to the east tomorrow morning. In
addition, skies will remain mostly clear with a few clouds aoa
10kft.
Southeast California/Southwest Arizona including KIPL and KBLH:
Mainly clear skies to prevail through the taf period. Winds to
remain mainly out of the south at KBLH, with sustained speeds as
high as 15 kts and a few gusts up to 20 kts possible during the late
afternoon/early evening hours. Winds at KIPL to mainly follow
typical diurnal trends with speeds around 10 to 15 kts.
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Monday through Friday...
Temperatures will start a gradual "cooling" trend, with highs on
Monday around 110-115F dropping into the 100-110F range by Friday.
Isolated thunderstorms are possible each afternoon/evening,
primarily over the higher terrain north and east of Phoenix on
Monday, and then over much of the desert southwest Tuesday through
Friday.
On Monday, given that conditions will remain dry in the lower levels
with minimum humidities generally between 10 and 20 percent, there
will be very little if any measurable rain. Mostly gusty erratic
winds and dry lightning will accompany storms potentially igniting
new fires or promoting the spread of existing fires.
Better chances for wetting rains is expected from Tuesday into
Friday as monsoon moisture levels increase over the region, with the
highest chances for rainfall still remaining over the higher terrain
of south-central AZ. Also accompanying the storms will be gusty
erratic winds and lightning. Minimum humidities during the Tuesday
through Friday period will rise into the 15-25 percent range, with
fair to good overnight recoveries.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
Visit us on Facebook...Twitter...and at weather.gov/phoenix
DISCUSSION...AJ/CB
AVIATION...Hernandez
FIRE WEATHER...Hernandez
Area Forecast Discussion
National Weather Service Tucson AZ
240 PM MST FRI JUN 24 2016
.SYNOPSIS...Adequate moisture will be around through the weekend into
next week for daily afternoon and evening showers and thunderstorms,
especially south and east of Tucson. Daytime high temperatures will
run near normal.
&&
.DISCUSSION...Scattered showers and thunderstorms were confined to
areas mainly east of a Tucson to Nogales line this afternoon. Alert
gages indicate rainfall amounts have generally remained less than a
third of an inch. Both the HRRR and the 24/12z UA-WRFNAM seem to be
handling this convection well. In addition, the last several runs of
the HRRR have depicted an outflow boundary originating from near
Tucson propagating northwest toward the Phoenix area between 24/23z
and 25/02z. As such, have included a mention of patchy blowing dust
in the forecast for a few hours this evening for portions of Pinal
County near I-10. At this point...expect convection to continue
across eastern zones into the evening and begin to diminish sometime
around or just after sunset.
Otherwise...the synoptic scale pattern was defined by longwave
ridging over much of the CONUS with low pressure moving into
northwestern Montana, as well as another disturbance pushing
northwestward along the Mexico/Texas border. Over the next several
days, it looks as though this Mexican low will stall before slowly
starting to move eastward through Texas, rather than move in our
direction. This will allow high pressure take hold of the desert
southwest early next week, with the center of high pressure setting
up near the favorable four corners region (for daily convection) by
Tuesday/Wednesday. Thereafter, high pressure seems to wobble around
the southwestern states a little bit, but overall remain in a good
position to ensure daily chances for monsoon activity. Showers and
storms this weekend will do well to moisten up the lower levels of
the atmosphere, so we will probably be looking at better coverage of
measurable precip and some higher QPF`s by the middle to end of
next week.
Bottom line is a general ramp up in shower and storm coverage
through the weekend which will persist into next week. The forecast
challenge will then shift to determining which days will be "up" or
"down" in terms of coverage and storm severity. Temperatures will
generally remain near normal though the forecast period.
&&
.AVIATION...VALID THRU 26/00Z.
Isold to sctd -TSRA/-SHRA thru 25/03z mainly E and S of KTUS. Sctd
debris cloud cover overnight with slgt chc of -SHRA. Isold -TSRA
dvlpg Sat after 25/19z mainly E and S of KTUS. Sfc wind until this
evening W-NW at 10-20 kts with gusts near 25 kts. Sfc wind will be
vrbl in direction at less than 10 kts at other times. Aviation
discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Isolated to scattered showers and thunderstorms will
occur across southeast Arizona through next Thursday. The best
chance of wetting rains during much of the period will be east-to-
south of Tucson. Daytime minimum relative humidity values will
generally range from the mid teens to around 30 percent with fair to
good nighttime recovery. 20-foot winds through Sunday as well as
next Wednesday and Thursday will generally be terrain driven at less
than 15 mph. 20-foot winds Monday and Tuesday will generally be from
the east at 5-15 mph with gusts of 20-25 mph. The strongest speeds
Monday and Tuesday should prevail from shortly after sunrise into
the early afternoon hours.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Discussion...French
Aviation/Fire Weather...Glueck
AFDPSR
Area Forecast Discussion
National Weather Service Phoenix AZ
830 AM MST SAT JUN 25 2016
.SYNOPSIS...
A very warm air mass will keep temperatures above normal through at
least the first half of next week. A gradual increase in moisture
will seep into portions of Arizona later this week and into next
week leading to a threat for showers and thunderstorms. Rainfall
will initially be limited to high terrain areas, then finally move
towards lower desert communities as we move into next week.
&&
.DISCUSSION...
Woohoo! The low level monsoon moisture boundary (MMB) finally made
inroads into southeast AZ yesterday for the first time this year,
and showed gains this morning from the weather balloon soundings.
The monsoon moisture boundary as defined in a Sept 1993 paper by the
same author, "Weak Upper-Level Divergence and Its Role in Organizing
Mesoscale Convective Storms along the ARIZONA MONSOON MOISTURE
BOUNDARY" is basically the amount of boundary layer moisture
threshold point where C.A.P.E. first develops on an average
warm season weather balloon sounding in AZ, given soundings change
very little during this 3 month warm season/summer. 850-800 mb
dewpoint minimally needs to be 8 degrees C, and for a bonus 700 mb
dewpoints 4 degrees C. Together this points to an even deeper
leading edge monsoon moisture boundary.
This morning the Tucson balloon sounding measured an 800 mb
dewpoint of 8 degrees C and at 700 mb 6 deg C. This MMB also
extended from the White mountains in far east central AZ, southwest
through Tucson and Nogales. Correspondingly, and no surprise,
convective trigger temperatures in southeast AZ were as follows:
Tucson 101 deg F with a high fcst of 101 deg, Douglas 89 deg F with
a high fcst of 93, Globe/Miami 89 with a high fcst of 98, and Casa
Grande 106 with a high fcst of 106.
Additionally, water vapor and IR imagery show a stream of
moisture/cloudiness emanating from northwest Mexico, through
Southeast AZ, and into northwest New Mexico. This pattern will
remain quasi-stationary through Monday with a few weak 300/250 mb
perturbations, bursts of accelerating wind, and some weak difluence
to unweight the atmosphere to provide support for deep boundary
layer, minimal C.A.P.E. convective threats in southeast AZ.
Weather balloon soundings for the deserts and mountains outside of
southeast AZ, or the remainder of our Forecast Area are
operationally too dry for convective threats. However, there
could be an outflow boundary emanating from southeast AZ late in the
day or early evening with a threat of dust between Phoenx and
Casa Grande.
Current forecasts which focus any convective threats over the
distant mountains east and southeast of Phoenix this weekend look
ok for now. No updates planned.
.PREVIOUS DISCUSSION...453 AM MST...
Early this morning, in the wake of troffing that passed by well to
our north, flow aloft over Arizona had turned to the west and
southwest as seen in the recent 00z AZ raobs as well as upper plot
data. Moisture, at least over eastern Arizona, remained a bit
elevated with a pwat of 1.16 inches at Tucson. Surface dewpoints
over the central deserts at 2 am were mostly in the 40s, values a
bit below typical monsoon thresholds. Latest IR imagery showed
partly cloudy skies east of Globe but west of southern Gila County
skies were clear.
Model guidance has not changed much over the past day or two and
still calls for just a very gradual import of moisture from the
southeast over the weekend, with most of the convective activity to
remain focused over higher terrain areas to the east and southeast
of Phoenix - mostly across southeast Arizona from Tucson east. A
weak inverted trof slowly creeps westward with time and steering flow
becomes weakly east/southeast with speeds around 5-10kt. Deeper
moisture stays east of Phoenix through Sunday evening and CAPE
values over the higher terrain of southern Gila County still appear
minimal, mostly below 300 j/kg. As such, POPs over the lower deserts
today and Sunday will mostly stay in the single digits with just
slight chances expected across the higher terrain east of Phoenix.
High temps will stay above seasonal normals, and actually will climb
a degree or two Sunday as high pressure aloft starts to strengthen
again. By Sunday, we should see highs in Phoenix reach around 111
with hotter western deserts climbing to around 113. Still, these
values will stay mostly near or just below heat warning thresholds
based on our heat impact level data. Once again, rain over the
deserts this weekend is a slim bet but there remains a somewhat
better chance for some blowing dust to work into portions of the
central deserts, mainly the southeast Phoenix metropolitan area and
portions of northern/northwest Pinal county such as Casa Grande and
the I-10 corridor southeast of Phoenix.
The idea of keeping convection and associated rainfall mainly over
higher terrain areas east/southeast of Phoenix this weekend is
supported by various mesoscale models such as the WRK4KM and the
NMM6KM.
On Monday, progs agree that the upper high will continue to build to
our north and become centered near the Utah border over far
northcentral AZ, with a high center around 597DM. The orientation of
the high will allow for a much more monsoonal flow pattern to set up
with deeper easterly flow overspreading much of the lower deserts
and bringing pwat values over 1 inch into the far western deserts
and even into southeast CA. Still, the real deep lower level
moisture such as 850mb dewpoints over 10C remain east of Phoenix and
CAPE will still be minimal into the lower elevations. Due to the
more favorable steering flow and better moisture profile, we will
still call for slight chances of afternoon and evening thunderstorms
spreading into the south central deserts Monday, with chances
developing over the higher terrain east of Phoenix. With the very
warm air aloft, and the air over the western deserts still somewhat
on the dry side we can expect additional warming with high temps
reaching around 114 over the hotter western deserts Monday. Highs in
the Phoenix area will stay around 111. Overall, despite the warming
high temps will stay around but mostly a bit below excessive heat
warning thresholds Monday and we do not plan on issuing a heat watch
at this time.
Tuesday through Friday...Model guidance including NAEFS and GEFS
ensemble guidance continues to suggest that our flow pattern is
setting up in a standard monsoonal fashion, with the upper high
migrating towards the vicinity of the four corners, and a much
deeper and widespread southeast steering flow working its way over
the AZ deserts and even into southeast CA. Moisture continues to
work across the lower deserts and rainfall chances will increase
with slight chances developing to the lower Colorado River valley
and potentially into the deserts of southeast CA. We have raised
POPs over much of the CWA correspondingly, with chance numbers over
the higher terrain of southern Gila County and slight chances over
much of the southcentral deserts westward. High temperatures take a
slow decline day to day as humidity values rise.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
Weak sfc pressure gradients to keep winds on the light side, mainly
aob 10 kts through the taf period, mostly following typical diurnal
trends. Few-sct high cirrus cloud layers this morning to give way to
sct-bkn mid-high cloud layers on this aft/evening as debris clouds
from distant thunderstorms to the south and east spread over the PHX
area. There is also an outside chance that outflows from these storms
could affect one or more of the PHX area terminals, with gusty winds
and blowing dust, but confidence is too low to include them in the
tafs at this time.
Southeast California/Southwest Arizona including KIPL and KBLH:
Mainly clear skies to prevail through the taf period. Winds to
remain mainly out of the south at KBLH and mainly follow typical
diurnal trends at KIPL.
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Monday through Friday...
Temperatures will start a gradual "cooling" trend, with highs on
Monday around 110-115F dropping into the 100-110F range by Friday.
Isolated thunderstorms are possible each afternoon/evening,
primarily over the higher terrain north and east of Phoenix on
Monday, and then over much of the desert southwest Tuesday through
Friday.
On Monday, given that conditions will remain dry in the lower levels
with minimum humidities generally between 10 and 20 percent, there
will be very little if any measurable rain. Mostly gusty erratic
winds and dry lightning will accompany storms potentially igniting
new fires or promoting the spread of existing fires.
Better chances for wetting rains is expected from Tuesday into
Friday as monsoon moisture levels increase over the region, with the
highest chances for rainfall still remaining over the higher terrain
of south-central AZ. Also accompanying the storms will be gusty
erratic winds and lightning. Minimum humidities during the Tuesday
through Friday period will rise into the 15-25 percent range, with
fair to good overnight recoveries.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
Visit us on Facebook...Twitter...and at weather.gov/phoenix
DISCUSSION...Vasquez/CB
AVIATION...Percha/Kuhlman
FIRE WEATHER...Hernandez
Area Forecast Discussion
National Weather Service Phoenix AZ
453 AM MST SAT JUN 25 2016
.SYNOPSIS...
A very warm air mass will keep temperatures above normal through at
least the first half of next week. A gradual increase in moisture
will seep into portions of Arizona later this week and into next
week leading to a threat for showers and thunderstorms. Rainfall
will initially be limited to high terrain areas, then finally move
towards lower desert communities as we move into next week.
&&
.DISCUSSION...
Early this morning, in the wake of troffing that passed by well to
our north, flow aloft over Arizona had turned to the west and
southwest as seen in the recent 00z AZ raobs as well as upper plot
data. Moisture, at least over eastern Arizona, remained a bit
elevated with a pwat of 1.16 inches at Tucson. Surface dewpoints
over the central deserts at 2 am were mostly in the 40s, values a
bit below typical monsoon thresholds. Latest IR imagery showed
partly cloudy skies east of Globe but west of southern Gila County
skies were clear.
Model guidance has not changed much over the past day or two and
still calls for just a very gradual import of moisture from the
southeast over the weekend, with most of the convective activity to
remain focused over higher terrain areas to the east and southeast
of Phoenix - mostly across southeast Arizona from Tucson east. A
weak inverted trof slowly creeps westward with time and steering flow
becomes weakly east/southeast with speeds around 5-10kt. Deeper
moisture stays east of Phoenix through Sunday evening and CAPE
values over the higher terrain of southern Gila County still appear
minimal, mostly below 300 j/kg. As such, POPs over the lower deserts
today and Sunday will mostly stay in the single digits with just
slight chances expected across the higher terrain east of Phoenix.
High temps will stay above seasonal normals, and actually will climb
a degree or two Sunday as high pressure aloft starts to strengthen
again. By Sunday, we should see highs in Phoenix reach around 111
with hotter western deserts climbing to around 113. Still, these
values will stay mostly near or just below heat warning thresholds
based on our heat impact level data. Once again, rain over the
deserts this weekend is a slim bet but there remains a somewhat
better chance for some blowing dust to work into portions of the
central deserts, mainly the southeast Phoenix metropolitan area and
portions of northern/northwest Pinal county such as Casa Grande and
the I-10 corridor southeast of Phoenix.
The idea of keeping convection and associated rainfall mainly over
higher terrain areas east/southeast of Phoenix this weekend is
supported by various mesocale models such as the WRK4KM and the
NMM6KM.
On Monday, progs agree that the upper high will continue to build to
our north and become centered near the Utah border over far
northcentral AZ, with a high center around 597DM. The orientation of
the high will allow for a much more monsoonal flow pattern to set up
with deeper easterly flow overspreading much of the lower deserts
and bringing pwat values over 1 inch into the far western deserts
and even into southeast CA. Still, the real deep lower level
moisture such as 850mb dewpoints over 10C remain east of Phoenix and
CAPE will still be minimal into the lower elevations. Due to the
more favorable steering flow and better moisture profile, we will
still call for slight chances of afternoon and evening thunderstorms
spreading into the south central deserts Monday, with chances
developing over the higher terrain east of Phoenix. With the very
warm air aloft, and the air over the western deserts still somewhat
on the dry side we can expect additional warming with high temps
reaching around 114 over the hotter western deserts Monday. Highs in
the Phoenix area will stay around 111. Overall, despite the warming
high temps will stay around but mostly a bit below excessive heat
warning thresholds Monday and we do not plan on issuing a heat watch
at this time.
Tuesday through Friday...Model guidance including NAEFS and GEFS
ensemble guidance continues to suggest that our flow pattern is
setting up in a standard monsoonal fashion, with the upper high
migrating towards the vicinity of the four corners, and a much
deeper and widespread southeast steering flow working its way over
the AZ deserts and even into southeast CA. Moisture continues to
work across the lower deserts and rainfall chances will increase
with slight chances developing to the lower Colorado River valley
and potentially into the deserts of southeast CA. We have raised
POPs over much of the CWA correspondingly, with chance numbers over
the higher terrain of southern Gila County and slight chances over
much of the southcentral deserts westward. High temperatures take a
slow decline day to day as humidity values rise.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
Weak sfc pressure gradients to keep winds on the light side, mainly
aob 10 kts through the taf period, mostly following typical diurnal
trends. Few-sct high cirrus cloud layers this morning to give way to
sct-bkn mid-high cloud layers on this aft/evening as debris clouds
from distant thunderstorms to the south and east spread over the PHX
area. There is also an outside chance that outflows from these storms
could affect one or more of the PHX area terminals, with gusty winds
and blowing dust, but confidence is too low to include them in the
tafs at this time.
Southeast California/Southwest Arizona including KIPL and KBLH:
Mainly clear skies to prevail through the taf period. Winds to
remain mainly out of the south at KBLH and mainly follow typical
diurnal trends at KIPL.
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Monday through Friday...
Temperatures will start a gradual "cooling" trend, with highs on
Monday around 110-115F dropping into the 100-110F range by Friday.
Isolated thunderstorms are possible each afternoon/evening,
primarily over the higher terrain north and east of Phoenix on
Monday, and then over much of the desert southwest Tuesday through
Friday.
On Monday, given that conditions will remain dry in the lower levels
with minimum humidities generally between 10 and 20 percent, there
will be very little if any measurable rain. Mostly gusty erratic
winds and dry lightning will accompany storms potentially igniting
new fires or promoting the spread of existing fires.
Better chances for wetting rains is expected from Tuesday into
Friday as monsoon moisture levels increase over the region, with the
highest chances for rainfall still remaining over the higher terrain
of south-central AZ. Also accompanying the storms will be gusty
erratic winds and lightning. Minimum humidities during the Tuesday
through Friday period will rise into the 15-25 percent range, with
fair to good overnight recoveries.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
Visit us on Facebook...Twitter...and at weather.gov/phoenix
DISCUSSION...CB
AVIATION...Percha/Kuhlman
FIRE WEATHER...Hernandez
Area Forecast Discussion
National Weather Service Phoenix AZ
453 AM MST SAT JUN 25 2016
.SYNOPSIS...
A very warm air mass will keep temperatures above normal through at
least the first half of next week. A gradual increase in moisture
will seep into portions of Arizona later this week and into next
week leading to a threat for showers and thunderstorms. Rainfall
will initially be limited to high terrain areas, then finally move
towards lower desert communities as we move into next week.
&&
.DISCUSSION...
Early this morning, in the wake of troffing that passed by well to
our north, flow aloft over Arizona had turned to the west and
southwest as seen in the recent 00z AZ raobs as well as upper plot
data. Moisture, at least over eastern Arizona, remained a bit
elevated with a pwat of 1.16 inches at Tucson. Surface dewpoints
over the central deserts at 2 am were mostly in the 40s, values a
bit below typical monsoon thresholds. Latest IR imagery showed
partly cloudy skies east of Globe but west of southern Gila County
skies were clear.
Model guidance has not changed much over the past day or two and
still calls for just a very gradual import of moisture from the
southeast over the weekend, with most of the convective activity to
remain focused over higher terrain areas to the east and southeast
of Phoenix - mostly across southeast Arizona from Tucson east. A
weak inverted trof slowly creeps westward with time and steering flow
becomes weakly east/southeast with speeds around 5-10kt. Deeper
moisture stays east of Phoenix through Sunday evening and CAPE
values over the higher terrain of southern Gila County still appear
minimal, mostly below 300 j/kg. As such, POPs over the lower deserts
today and Sunday will mostly stay in the single digits with just
slight chances expected across the higher terrain east of Phoenix.
High temps will stay above seasonal normals, and actually will climb
a degree or two Sunday as high pressure aloft starts to strengthen
again. By Sunday, we should see highs in Phoenix reach around 111
with hotter western deserts climbing to around 113. Still, these
values will stay mostly near or just below heat warning thresholds
based on our heat impact level data. Once again, rain over the
deserts this weekend is a slim bet but there remains a somewhat
better chance for some blowing dust to work into portions of the
central deserts, mainly the southeast Phoenix metropolitan area and
portions of northern/northwest Pinal county such as Casa Grande and
the I-10 corridor southeast of Phoenix.
The idea of keeping convection and associated rainfall mainly over
higher terrain areas east/southeast of Phoenix this weekend is
supported by various mesocale models such as the WRK4KM and the
NMM6KM.
On Monday, progs agree that the upper high will continue to build to
our north and become centered near the Utah border over far
northcentral AZ, with a high center around 597DM. The orientation of
the high will allow for a much more monsoonal flow pattern to set up
with deeper easterly flow overspreading much of the lower deserts
and bringing pwat values over 1 inch into the far western deserts
and even into southeast CA. Still, the real deep lower level
moisture such as 850mb dewpoints over 10C remain east of Phoenix and
CAPE will still be minimal into the lower elevations. Due to the
more favorable steering flow and better moisture profile, we will
still call for slight chances of afternoon and evening thunderstorms
spreading into the south central deserts Monday, with chances
developing over the higher terrain east of Phoenix. With the very
warm air aloft, and the air over the western deserts still somewhat
on the dry side we can expect additional warming with high temps
reaching around 114 over the hotter western deserts Monday. Highs in
the Phoenix area will stay around 111. Overall, despite the warming
high temps will stay around but mostly a bit below excessive heat
warning thresholds Monday and we do not plan on issuing a heat watch
at this time.
Tuesday through Friday...Model guidance including NAEFS and GEFS
ensemble guidance continues to suggest that our flow pattern is
setting up in a standard monsoonal fashion, with the upper high
migrating towards the vicinity of the four corners, and a much
deeper and widespread southeast steering flow working its way over
the AZ deserts and even into southeast CA. Moisture continues to
work across the lower deserts and rainfall chances will increase
with slight chances developing to the lower Colorado River valley
and potentially into the deserts of southeast CA. We have raised
POPs over much of the CWA correspondingly, with chance numbers over
the higher terrain of southern Gila County and slight chances over
much of the southcentral deserts westward. High temperatures take a
slow decline day to day as humidity values rise.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
Weak sfc pressure gradients to keep winds on the light side, mainly
aob 10 kts through the taf period, mostly following typical diurnal
trends. Few-sct high cirrus cloud layers this morning to give way to
sct-bkn mid-high cloud layers on this aft/evening as debris clouds
from distant thunderstorms to the south and east spread over the PHX
area. There is also an outside chance that outflows from these storms
could affect one or more of the PHX area terminals, with gusty winds
and blowing dust, but confidence is too low to include them in the
tafs at this time.
Southeast California/Southwest Arizona including KIPL and KBLH:
Mainly clear skies to prevail through the taf period. Winds to
remain mainly out of the south at KBLH and mainly follow typical
diurnal trends at KIPL.
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Monday through Friday...
Temperatures will start a gradual "cooling" trend, with highs on
Monday around 110-115F dropping into the 100-110F range by Friday.
Isolated thunderstorms are possible each afternoon/evening,
primarily over the higher terrain north and east of Phoenix on
Monday, and then over much of the desert southwest Tuesday through
Friday.
On Monday, given that conditions will remain dry in the lower levels
with minimum humidities generally between 10 and 20 percent, there
will be very little if any measurable rain. Mostly gusty erratic
winds and dry lightning will accompany storms potentially igniting
new fires or promoting the spread of existing fires.
Better chances for wetting rains is expected from Tuesday into
Friday as monsoon moisture levels increase over the region, with the
highest chances for rainfall still remaining over the higher terrain
of south-central AZ. Also accompanying the storms will be gusty
erratic winds and lightning. Minimum humidities during the Tuesday
through Friday period will rise into the 15-25 percent range, with
fair to good overnight recoveries.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
Visit us on Facebook...Twitter...and at weather.gov/phoenix
DISCUSSION...CB
AVIATION...Percha/Kuhlman
FIRE WEATHER...Hernandez
[top]
Area Forecast Discussion
National Weather Service Flagstaff AZ
445 AM MST SAT JUN 25 2016
.SYNOPSIS...Expect mainly dry and continued hot conditions heading
into the weekend, with a few showers or thunderstorms to the east of
Flagstaff. Moisture will slowly return by early next week as a more
monsoonal type of circulation develops, leading to increased shower
and thunderstorm activity and more seasonable temperatures.
&&
.DISCUSSION...Very dry air aloft covers most of Arizona as westerly
flow continues. The exception is over far eastern Arizona, where a
fairly obvious plume of monsoonal moisture persists. A s/wv over
western Montana will keep this plume where it is today, maybe even
push it a bit further east. Behind this s/wv, westerly flow will
relax Sunday and heading into next week.
Models show high pressure building and moving back west. This will
open the door for the monsoonal airmass to move back west and north
through much of next week. The flow pattern really starts to look
good later in the week as hghts fall and the high consolidates over
New Mexico. We kept with the previous thinking of slowly raising
pops each day from Sunday onward, while steadily pushing the monsoon
boundary westward and lowering temperatures each day.
&&
.AVIATION...For the 12Z Package...Expect widely scattered showers
and thunderstorms east of a KPAN-Krqe line btwn 18Z Sat -02z Sun.
Otherwise, expect VFR conditions. Smoke downwind of area wildfires
may impact visibility at times. Aviation discussion not updated for
TAF amendments.
&&
.FIRE WEATHER...Dry air aloft to cover most of northern Arizona
today, and limit limit shower and thunderstorm coverage to the
higher terrain in Apache county. These high based thunderstorms may
produce erratic gusty winds.
Sunday through Wednesday...Additional mid level moisture begins to
move in from the south and southeast on Sunday and Monday as we
transition into a monsoonal flow pattern. High based storms should
be increasing in coverage, with the threat of strong outflow winds
expanding across the northland.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...Peterson
AVIATION...DL
FIRE WEATHER...DL
For Northern Arizona weather information visit
weather.gov/flagstaff
[top]
Area Forecast Discussion
National Weather Service Tucson AZ
415 AM MST SAT JUN 25 2016
.SYNOPSIS...Isolated to scattered showers and thunderstorms will
occur mainly east and south of Tucson this weekend. A more favorable
flow regime will then provide increased coverage of showers and
thunderstorms Monday through Friday. High temperatures will be near
normal or a few degrees below normal.
&&
.DISCUSSION...Strong high pressure aloft early this morning was
centered west of northern Baja California near 30N/125W. Meanwhile,
a closed upper low was centered over nern Montana, and a broad upper
low was centered just south of the Texas Big Bend region. IR/water
vapor satellite imagery depicted mostly cloudy to cloudy skies from
Tucson east to the New Mexico border, and clear skies across western
sections of this forecast area. Isolated showers producing mostly
virga has occurred much of the overnight hours across Greenlee,
Graham and Cochise counties east of Tucson.
Several HRRR solutions have been similar with depicting the ongoing
very light precip area to either expand or move westward toward the
Tucson metro area and further southward into Santa Cruz County later
this morning. Given the light generally swly mid-level flow regime
across the area, am not necessarily inclined to agree with these
solutions.
However, another plausible scenario for the development of showers
and thunderstorms later today would be adjacent the boundary
separating the deeper moisture from Tucson eastward, and the drier
air across western sections as depicted via water vapor imagery.
At any rate, have maintained isolated to scattered coverage of
showers and thunderstorms across much of the area into this evening.
The best precip chances will be east-to-south of Tucson. Given the
fairly dry near-surface environment, have also maintained patchy
blowing dust late this afternoon and early this evening essentially
along the I-10 corridor from Tucson nwwd into south central Pinal
County. The 25/00Z NAM/GFS/ECMWF/CMC and 25/03Z SREF all suggest
that precip coverage would decrease somewhat Sunday. However, only
slightly decreased PoPs are depicted in the official forecast for
Sunday afternoon/evening. Have again depicted patchy blowing dust
late Sunday afternoon and early Sunday evening for locales northwest
of Tucson.
25/00Z GFS/ECMWF/CMC were then in very good agreement with developing
a deeper easterly flow regime across southeast Arizona Monday into
Tuesday. This flow pattern is in response to strong high pressure
aloft becoming centered over southern Utah. At any rate, the
coverage of showers/tstms starting Monday should increase across the
area, and PoPs were raised somewhat to reflect this notion. The NAM
and CMC are suggesting that Monday afternoon/evening may potentially
be fairly active, as an inverted trough/weak closed upper low
approaches from the southeast.
Thereafter, high pressure aloft is progged to become centered over
the Four Corners region Wednesday, and then the upper high
eventually becomes centered further southeast over west Texas
Friday. Have noted that the ECMWF is markedly more robust with QPF
fields versus the GFS. The upshot is that a fairly light sely/sly
mid-level flow regime will maintain adequate moisture to support the
continuation of at least slight chance PoPs during the latter part
of next week.
High temps for the Tucson metro area and locales west-to-northwest
of Tucson will be near normal. However, daytime temps for locales
east-to-south of Tucson, including Safford, Douglas and Nogales will
average a few degs below normal thru much of this forecast period.
&&
.AVIATION...VALID THRU 26/12Z.
Isolated -SHRA this morning east of KTUS, then isolated to scattered
-TSRA/-SHRA mainly east-to-south of KTUS this afternoon into Sunday
morning. Otherwise, mostly clear skies will prevail west of KTUS
thru the period. KTUS vicinity east and south expect cloud decks
ranging from 10k-15k ft msl. Surface wind will generally be less
than 10 kts into early Sunday morning. However, surface wind this
afternoon vicinity KSAD will be wly/nwly at 12-16 kts with gusts to
near 20 kts. Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Expect isolated to scattered showers and
thunderstorms mainly east and south of Tucson this weekend. Greater
coverage of showers and thunderstorms should then occur Monday
through next Friday. Otherwise, daytime minimum relative humidity
values will generally range from the mid teens to around 30 percent
with fair to good nighttime recovery. 20-foot winds this weekend as
well as Wednesday through Friday will be terrain driven at less than
15 mph. 20-foot winds Monday and Tuesday will generally be from
the east at 5-15 mph with gusts of 15-20 mph. The strongest speeds
Monday and Tuesday should prevail from shortly after sunrise into
the early afternoon hours.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Francis
Area Forecast Discussion
National Weather Service Phoenix AZ
405 PM MST SAT JUN 25 2016
...Retransmission...
.SYNOPSIS...
A very warm air mass will keep temperatures above normal through at
least the first half of next week. A gradual increase in moisture
will seep into portions of Arizona later this weekend and into next
week, leading to a threat for showers and thunderstorms. Rainfall
will initially be limited to the higher terrain, then finally move
towards lower deserts as we move into next week.
&&
.DISCUSSION...
Tonight and Sunday...
Forecast for the next 7 days are going to be quite challenging with
regards to thunderstorm threats as low/mid level moisture make a
slow creep from southeast AZ this weekend, west into the remainder
of the state throughout next week.
However for tonight and Sunday, most of our forecast area will be
dry with the exception of possible isolated thunderstorms over the
mountains of southern Gila County this evening, and again Sunday
evening. One thing that concerns us though, the models are
forecasting a large mid level inverted trof to develop over
northwest Mexico by late afternoon. We cant see it in the vapor
imagery, however models insist that its resultant broad cyclonic
circulation will rotate the bulk of convective debris clouds from
southeast AZ, into central and southern AZ tonight and Sunday
morning. This will mark the beginning of the slow westward moisture
push. Unfortunately the Guaymas sounding in northwest Mexico along
the Gulf coast has been missing for months now, so we cant get a
close look at this evolving feature from measured data, and will
have to default to the models and with their predictions of midlevel
moisture advection through Sunday.
Monday through Saturday...
A more established monsoon, in terms of moisture, is expected over
the southern half of AZ. The monsoon moisture boundary from
southeast AZ is expected to move into the Phoenix area by Tuesday,
then toward the lower Colorado River Valley by late Wednesday. In
other words, most of our southwest and south-central AZ zones will
be in the monsoon soup by the middle of next week, with enough
potential energy for possible convective threats, although its
really the little upper level nuances/perturbations that govern any
larger outbreaks, and or colliding outflow boundaries which are
difficult to discern this far in advance.
Therefore, as far as convective threats are concerned for next week,
we found that a broad brush approach to forecasting a slight chance
of convective threats nearly everywhere was best. This approach
actually started on the mid shift last night and accepted.
Another reason for the convective uncertainties involve the upper
level nuances/perturbations. Models forecast one large 300/250 mb
upper level inverted trof to move into southwest AZ from the
northern Gulf of CA on Monday, with several follow-up smaller
disturbances for the remainder of the week. Since the upper flow is
very weak over northern Mexico, which inherently make the models
less predictive or less reliable, and there are very few Mexican
weather balloon soundings launched, we will take a wait and see
position this far in advance before we jump on any one particular
day next week that could be convectively significant. Again a broad
brush slight chance of tstm approach is good for now, but hey, the
monsoon will be here.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
Gusty erratic winds and blowing dust from distant south and east AZ
storms will be possible this afternoon and early evening (after 00Z)
at Phoenix terminals. However, low confidence in exact spatial and
temporal coverage precludes mention in 18Z TAF. Outside of potential
storm outflows, winds will be on the light side, mainly aob 10 kts
throughout the TAF period, following typical diurnal trends. Few to
scattered high cirrus cloud layers this morning will become scattered
to broken mid-high cloud layers this afternoon/evening as a result of
debris clouds from distant thunderstorms.
Southeast California/Southwest Arizona including KIPL and KBLH:
Skies will remain mostly clear over both TAF sites. Winds will
remain out of the south at KBLH and out of the south to southeast at
KIPL, with speeds generally aob 10 kts accompanied by a few afternoon
gusts up to 15 to 20 kts.
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Tuesday through Saturday...
Temperatures will be on a "cooling" trend, with highs on Tuesday
around 108-115F dropping into the 102-110F range by Saturday.
As monsoon moisture levels increase over the region, isolated
thunderstorms are possible each afternoon/evening over much of the
desert southwest, with the highest chances over the higher terrain
of central and eastern Arizona. Accompanying any storm that develops
will be wetting rains, gusty erratic winds, and lightning. This
increase in moisture will support a rise in minimum humidities, with
values ranging in the 15-25 percent range each day with good
overnight recoveries. Outside of gusty storm winds, speeds will
range between 5 to 15 mph with a few afternoon upslope gusts up to
20 mph.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
Visit us on Facebook...Twitter...and at weather.gov/phoenix
DISCUSSION...Vasquez
AVIATION...Hernandez
FIRE WEATHER...Hernandez
[top]
Area Forecast Discussion
National Weather Service Flagstaff AZ
318 PM MST SAT JUN 25 2016
.SYNOPSIS...Dry and hot weather will remain over far western
Arizona through the weekend. Moisture will remain over central and
eastern Arizona...from about Flagstaff eastward...into early next
week. By Tuesday...the high pressure center will be in a position to
increase moisture over much of northern Arizona with increasing
shower and thunderstorm activity and more seasonable temperatures.
&&
.Discussion...Mid level moisture increased over northern Arizona
today. Strong surface heating was able to break the 500 mb inversion
that was present on the morning sounding. This allowed isolated to
scattered showers and thunderstorms to form.
Moisture will continue increase from the southeast-south this week.
This will allow shower and thunderstorm coverage to also increase.
The high will also weak some allowing high temperatures to drop to
near or below average for this time of year by mid week.
&&
.AVIATION...For the 00Z Package...Expect widely scattered
showers and thunderstorms in the White Mountains and Mogollon Rim
through 02Z. Shower activity will diminish overnight, before
returning from Sunday 18Z to Monday 03Z. Smoke downwind of active
wildfires may impact local visibility. Aviation discussion not
updated for TAF amendments.
&&
.FIRE WEATHER...Monsoon moisture will slowly increase northward each
day. Expect deeper moisture with increasing coverage in showers and
thunderstorms starting on Monday. Erratic and gusty outflow winds
possible near showers and thunderstorms.
Tuesday through Thursday...An active wet Monsoon weather pattern is
forecast with good shower and thunderstorm coverage each day across
northern Arizona.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...MAS
AVIATION...Bohlin
FIRE WEATHER...Bohlin
For Northern Arizona weather information visit
weather.gov/flagstaff
[top]
Area Forecast Discussion
National Weather Service Tucson AZ
302 PM MST SAT JUN 25 2016
.SYNOPSIS...We now have enough moisture for isolated to scattered
showers and thunderstorms this weekend. A more favorable flow
regime will then provide increased coverage of showers and
thunderstorms Monday through Friday.
&&
.DISCUSSION...We`re under a broad regime of mid level high
pressure, with anchors just off the northern coast of Baja, and
just east of Texas. In between there is a very nice inverted
trough pushing through southern and western Texas. This feature is
generating organized convection through portions of Texas and New
Mexico, however our flow regime is much weaker. We do have plenty
of moisture to work with, with precipitable water values between
1.2 and 1.4 inches. Our afternoon is going pretty much as expected
to this point, with increasing convection near a weak moisture
convergence area from central Pima county southward through Sonora
and Santa Cruz county. The southern half of Cochise county is
also getting in on the action with a bit more sun today than other
areas. Slow movement to the west and northwest will continue
through the mid evening hours and should push through eastern Pima
and into Pinal county later this afternoon and early evening.
For Sunday, some secondary consolidation in the broad scale mean
ridge position should tamp down convection with most favored
locations being the central mountains and international border
areas. Starting the day with what should still be a relatively
weaker flow will make storms initially reluctant to push away from
the mountains Sunday afternoon. However the UofA WRF-GFS is
hinting at a couple of nice strong outflows pushing west and
northwest late Sunday afternoon and early Sunday evening, filling
in valley locations and probably generating dust north of Tucson.
After that, as high pressure strengthens north of the area, the
first half of the new week should see a better flow regime
(albeit still on the weak side) for reinforcing deep moisture
and importing one or two weaknesses in the flow. This should
serve to anchor the entire week for seasonal convection.
&&
.AVIATION...VALID THRU 27/00Z.
Isolated to scattered -TSRA/-SHRA this afternoon into Sunday
morning, and then again Sunday afternoon. Cloud decks ranging
from 10k- 15k ft msl. Gusty outflows possible with storms,
otherwise surface wind will generally be less than 10 kts into
Sunday. However, surface wind this afternoon vicinity KSAD will
be wly/nwly at 12-16 kts with gusts to near 20 kts. Aviation
discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Expect isolated to scattered showers and
thunderstorms this weekend. Greater coverage of showers and
thunderstorms should then occur Monday through next Friday.
Otherwise, daytime minimum relative humidity values will generally
range from the mid teens to around 30 percent with fair to good
nighttime recovery. 20-foot winds this weekend as well as
Wednesday through Friday will be terrain driven at less than 15
mph. 20-foot winds Monday and Tuesday will generally be from the
east at 5-15 mph with gusts of 15-20 mph. The strongest speeds
Monday and Tuesday should prevail from shortly after sunrise into
the early afternoon hours.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Meyer/Rasmussen
Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Area Forecast Discussion...RESENT
National Weather Service Phoenix AZ
225 PM MST SAT JUN 25 2016
.SYNOPSIS...
A very warm air mass will keep temperatures above normal through at
least the first half of next week. A gradual increase in moisture
will seep into portions of Arizona later this weekend and into next
week, leading to a threat for showers and thunderstorms. Rainfall
will initially be limited to the higher terrain, then finally move
towards lower deserts as we move into next week.
&&
.DISCUSSION...
Tonight and Sunday...
Forecast for the next 7 days are going to be quite challenging with
regards to thunderstorm threats as low/mid level moisture make a
slow creep from southeast AZ this weekend, west into the remainder
of the state throughout next week.
However for tonight and Sunday, most of our forecast area will be
dry with the exception of possible isolated thunderstorms over the
mountains of soutern Gila County this evening, and again Sunday
evening. One thing that concerns us though, the models are
forecasting a large mid level inverted trof to develop over
northwest Mexico by late afternoon. We cant see it in the vapor
imagery, however models insist that its resultant broad cyclonic
circulation will rotate the bulk of convective debris clouds from
southeast AZ, into central and southern AZ tonight and Sunday
morning. This will mark the beginning of the slow westward moisture
push. Unfortunately the Guaymas sounding in northwest Mexico along
the Gulf coast has been missing for months now, so we cant get a
close look at this evolving feature from measured data, and will
have to default to the models and with their predictions of midlevel
moisture advection through Sunday.
Monday through Saturday...
A more established monsoon, in terms of moisture, is expected over
the southern half of AZ. The monsoon moisture boundary from
southeast AZ is expected to move into the Phoenix area by Tuesday,
then toward the lower Colorado River Valley by late Wednesday. In
other words, most of our southwest and south-central AZ zones will
be in the monsoon soup by the middle of next week, with enough
potential energy for possible convective threats, although its
really the little upper level nuances/perturbations that govern any
larger outbreaks, and or colliding outflow boundaries which are
difficult to discern this far in advance.
Therefore, as far as convective threats are concerned for next week,
we found that a broad brush approach to forecasting a slight chance
of convective threats nearly everywhere was best. This approach
actually started on the mid shift last night and accepted.
Another reason for the convective uncertainties involve the upper
level nuances/perterbations. Models forecast one large 300/250 mb
upper level inverted trof to move into southwest AZ from the
northern Gulf of CA on Monday, with several follow-up smaller
disturbances for the remainder of the week. Since the upper flow is
very weak over northern Mexico, which inherently make the models
less predictive or less reliable, and there are very few Mexican
weather balloon soundings launched, we will take a wait and see
position this far in advance before we jump on any one particular
day next week that could be convectively significant. Again a broad
brush slight chance of tstm approach is good for now, but hey, the
monsoon will be here.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
Gusty erratic winds and blowing dust from distant south and east AZ
storms will be possible this afternoon and early evening (after 00Z)
at Phoenix terminals. However, low confidence in exact spatial and
temporal coverage precludes mention in 18Z TAF. Outside of potential
storm outflows, winds will be on the light side, mainly aob 10 kts
throughout the TAF period, following typical diurnal trends. Few to
scattered high cirrus cloud layers this morning will become scattered
to broken mid-high cloud layers this afternoon/evening as a result of
debris clouds from distant thunderstorms.
Southeast California/Southwest Arizona including KIPL and KBLH:
Skies will remain mostly clear over both TAF sites. Winds will
remain out of the south at KBLH and out of the south to southeast at
KIPL, with speeds generally aob 10 kts accompanied by a few afternoon
gusts up to 15 to 20 kts.
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Tuesday through Saturday...
Temperatures will be on a "cooling" trend, with highs on Tuesday
around 108-115F dropping into the 102-110F range by Saturday.
As monsoon moisture levels increase over the region, isolated
thunderstorms are possible each afternoon/evening over much of the
desert southwest, with the highest chances over the higher terrain
of central and eastern Arizona. Accompanying any storm that develops
will be wetting rains, gusty erratic winds, and lightning. This
increase in moisture will support a rise in minimum humidities, with
values ranging in the 15-25 percent range each day with good
overnight recoveries. Outside of gusty storm winds, speeds will
range between 5 to 15 mph with a few afternoon upslope gusts up to
20 mph.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
Visit us on Facebook...Twitter...and at weather.gov/phoenix
DISCUSSION...Vasquez
AVIATION...Hernandez
FIRE WEATHER...Hernandez
Area Forecast Discussion
National Weather Service Phoenix AZ
1043 AM MST SAT JUN 25 2016
.UPDATE...Updated Aviation Discussion...
&&
.SYNOPSIS...
A very warm air mass will keep temperatures above normal through at
least the first half of next week. A gradual increase in moisture
will seep into portions of Arizona later this week and into next
week leading to a threat for showers and thunderstorms. Rainfall
will initially be limited to high terrain areas, then finally move
towards lower desert communities as we move into next week.
&&
.DISCUSSION...
Woohoo! The low level monsoon moisture boundary (MMB) finally made
inroads into southeast AZ yesterday for the first time this year,
and showed gains this morning from the weather balloon soundings.
The monsoon moisture boundary as defined in a Sept 1993 paper by the
same author, "Weak Upper-Level Divergence and Its Role in Organizing
Mesoscale Convective Storms along the ARIZONA MONSOON MOISTURE
BOUNDARY" is basically the amount of boundary layer moisture
threshold point where C.A.P.E. first develops on an average
warm season weather balloon sounding in AZ, given soundings change
very little during this 3 month warm season/summer. 850-800 mb
dewpoint minimally needs to be 8 degrees C, and for a bonus 700 mb
dewpoints 4 degrees C. Together this points to an even deeper
leading edge monsoon moisture boundary.
This morning the Tucson balloon sounding measured an 800 mb
dewpoint of 8 degrees C and at 700 mb 6 deg C. This MMB also
extended from the White mountains in far east central AZ, southwest
through Tucson and Nogales. Correspondingly, and no surprise,
convective trigger temperatures in southeast AZ were as follows:
Tucson 101 deg F with a high fcst of 101 deg, Douglas 89 deg F with
a high fcst of 93, Globe/Miami 89 with a high fcst of 98, and Casa
Grande 106 with a high fcst of 106.
Additionally, water vapor and IR imagery show a stream of
moisture/cloudiness emanating from northwest Mexico, through
Southeast AZ, and into northwest New Mexico. This pattern will
remain quasi-stationary through Monday with a few weak 300/250 mb
perturbations, bursts of accelerating wind, and some weak difluence
to unweight the atmosphere to provide support for deep boundary
layer, minimal C.A.P.E. convective threats in southeast AZ.
Weather balloon soundings for the deserts and mountains outside of
southeast AZ, or the remainder of our Forecast Area are
operationally too dry for convective threats. However, there
could be an outflow boundary emanating from southeast AZ late in the
day or early evening with a threat of dust between Phoenix and
Casa Grande.
Current forecasts which focus any convective threats over the
distant mountains east and southeast of Phoenix this weekend look
ok for now. No updates planned.
.PREVIOUS DISCUSSION...453 AM MST...
Early this morning, in the wake of troffing that passed by well to
our north, flow aloft over Arizona had turned to the west and
southwest as seen in the recent 00z AZ raobs as well as upper plot
data. Moisture, at least over eastern Arizona, remained a bit
elevated with a pwat of 1.16 inches at Tucson. Surface dewpoints
over the central deserts at 2 am were mostly in the 40s, values a
bit below typical monsoon thresholds. Latest IR imagery showed
partly cloudy skies east of Globe but west of southern Gila County
skies were clear.
Model guidance has not changed much over the past day or two and
still calls for just a very gradual import of moisture from the
southeast over the weekend, with most of the convective activity to
remain focused over higher terrain areas to the east and southeast
of Phoenix - mostly across southeast Arizona from Tucson east. A
weak inverted trof slowly creeps westward with time and steering flow
becomes weakly east/southeast with speeds around 5-10kt. Deeper
moisture stays east of Phoenix through Sunday evening and CAPE
values over the higher terrain of southern Gila County still appear
minimal, mostly below 300 j/kg. As such, POPs over the lower deserts
today and Sunday will mostly stay in the single digits with just
slight chances expected across the higher terrain east of Phoenix.
High temps will stay above seasonal normals, and actually will climb
a degree or two Sunday as high pressure aloft starts to strengthen
again. By Sunday, we should see highs in Phoenix reach around 111
with hotter western deserts climbing to around 113. Still, these
values will stay mostly near or just below heat warning thresholds
based on our heat impact level data. Once again, rain over the
deserts this weekend is a slim bet but there remains a somewhat
better chance for some blowing dust to work into portions of the
central deserts, mainly the southeast Phoenix metropolitan area and
portions of northern/northwest Pinal county such as Casa Grande and
the I-10 corridor southeast of Phoenix.
The idea of keeping convection and associated rainfall mainly over
higher terrain areas east/southeast of Phoenix this weekend is
supported by various mesoscale models such as the WRK4KM and the
NMM6KM.
On Monday, progs agree that the upper high will continue to build to
our north and become centered near the Utah border over far
northcentral AZ, with a high center around 597DM. The orientation of
the high will allow for a much more monsoonal flow pattern to set up
with deeper easterly flow overspreading much of the lower deserts
and bringing pwat values over 1 inch into the far western deserts
and even into southeast CA. Still, the real deep lower level
moisture such as 850mb dewpoints over 10C remain east of Phoenix and
CAPE will still be minimal into the lower elevations. Due to the
more favorable steering flow and better moisture profile, we will
still call for slight chances of afternoon and evening thunderstorms
spreading into the south central deserts Monday, with chances
developing over the higher terrain east of Phoenix. With the very
warm air aloft, and the air over the western deserts still somewhat
on the dry side we can expect additional warming with high temps
reaching around 114 over the hotter western deserts Monday. Highs in
the Phoenix area will stay around 111. Overall, despite the warming
high temps will stay around but mostly a bit below excessive heat
warning thresholds Monday and we do not plan on issuing a heat watch
at this time.
Tuesday through Friday...Model guidance including NAEFS and GEFS
ensemble guidance continues to suggest that our flow pattern is
setting up in a standard monsoonal fashion, with the upper high
migrating towards the vicinity of the four corners, and a much
deeper and widespread southeast steering flow working its way over
the AZ deserts and even into southeast CA. Moisture continues to
work across the lower deserts and rainfall chances will increase
with slight chances developing to the lower Colorado River valley
and potentially into the deserts of southeast CA. We have raised
POPs over much of the CWA correspondingly, with chance numbers over
the higher terrain of southern Gila County and slight chances over
much of the southcentral deserts westward. High temperatures take a
slow decline day to day as humidity values rise.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
Gusty erratic winds and blowing dust from distant south and east AZ
storms will be possible this afternoon and early evening (after 00Z)
at Phoenix terminals. However, low confidence in exact spatial and
temporal coverage precludes mention in 18Z TAF. Outside of potential
storm outflows, winds will be on the light side, mainly aob 10 kts
throughout the TAF period, following typical diurnal trends. Few to
scattered high cirrus cloud layers this morning will become scattered
to broken mid-high cloud layers this afternoon/evening as a result of
debris clouds from distant thunderstorms.
Southeast California/Southwest Arizona including KIPL and KBLH:
Skies will remain mostly clear over both TAF sites. Winds will
remain out of the south at KBLH and out of the south to southeast at
KIPL, with speeds generally aob 10 kts accompanied by a few afternoon
gusts up to 15 to 20 kts.
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Monday through Friday...
Temperatures will start a gradual "cooling" trend, with highs on
Monday around 110-115F dropping into the 100-110F range by Friday.
Isolated thunderstorms are possible each afternoon/evening,
primarily over the higher terrain north and east of Phoenix on
Monday, and then over much of the desert southwest Tuesday through
Friday.
On Monday, given that conditions will remain dry in the lower levels
with minimum humidities generally between 10 and 20 percent, there
will be very little if any measurable rain. Mostly gusty erratic
winds and dry lightning will accompany storms potentially igniting
new fires or promoting the spread of existing fires.
Better chances for wetting rains is expected from Tuesday into
Friday as monsoon moisture levels increase over the region, with the
highest chances for rainfall still remaining over the higher terrain
of south-central AZ. Also accompanying the storms will be gusty
erratic winds and lightning. Minimum humidities during the Tuesday
through Friday period will rise into the 15-25 percent range, with
fair to good overnight recoveries.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
Visit us on Facebook...Twitter...and at weather.gov/phoenix
DISCUSSION...Vasquez/CB
AVIATION...Hernandez
FIRE WEATHER...Hernandez
Area Forecast Discussion
National Weather Service Phoenix AZ
1043 AM MST SAT JUN 25 2016
.UPDATE...Updated Aviation Discussion...
&&
.SYNOPSIS...
A very warm air mass will keep temperatures above normal through at
least the first half of next week. A gradual increase in moisture
will seep into portions of Arizona later this week and into next
week leading to a threat for showers and thunderstorms. Rainfall
will initially be limited to high terrain areas, then finally move
towards lower desert communities as we move into next week.
&&
.DISCUSSION...
Woohoo! The low level monsoon moisture boundary (MMB) finally made
inroads into southeast AZ yesterday for the first time this year,
and showed gains this morning from the weather balloon soundings.
The monsoon moisture boundary as defined in a Sept 1993 paper by the
same author, "Weak Upper-Level Divergence and Its Role in Organizing
Mesoscale Convective Storms along the ARIZONA MONSOON MOISTURE
BOUNDARY" is basically the amount of boundary layer moisture
threshold point where C.A.P.E. first develops on an average
warm season weather balloon sounding in AZ, given soundings change
very little during this 3 month warm season/summer. 850-800 mb
dewpoint minimally needs to be 8 degrees C, and for a bonus 700 mb
dewpoints 4 degrees C. Together this points to an even deeper
leading edge monsoon moisture boundary.
This morning the Tucson balloon sounding measured an 800 mb
dewpoint of 8 degrees C and at 700 mb 6 deg C. This MMB also
extended from the White mountains in far east central AZ, southwest
through Tucson and Nogales. Correspondingly, and no surprise,
convective trigger temperatures in southeast AZ were as follows:
Tucson 101 deg F with a high fcst of 101 deg, Douglas 89 deg F with
a high fcst of 93, Globe/Miami 89 with a high fcst of 98, and Casa
Grande 106 with a high fcst of 106.
Additionally, water vapor and IR imagery show a stream of
moisture/cloudiness emanating from northwest Mexico, through
Southeast AZ, and into northwest New Mexico. This pattern will
remain quasi-stationary through Monday with a few weak 300/250 mb
perturbations, bursts of accelerating wind, and some weak difluence
to unweight the atmosphere to provide support for deep boundary
layer, minimal C.A.P.E. convective threats in southeast AZ.
Weather balloon soundings for the deserts and mountains outside of
southeast AZ, or the remainder of our Forecast Area are
operationally too dry for convective threats. However, there
could be an outflow boundary emanating from southeast AZ late in the
day or early evening with a threat of dust between Phoenix and
Casa Grande.
Current forecasts which focus any convective threats over the
distant mountains east and southeast of Phoenix this weekend look
ok for now. No updates planned.
.PREVIOUS DISCUSSION...453 AM MST...
Early this morning, in the wake of troffing that passed by well to
our north, flow aloft over Arizona had turned to the west and
southwest as seen in the recent 00z AZ raobs as well as upper plot
data. Moisture, at least over eastern Arizona, remained a bit
elevated with a pwat of 1.16 inches at Tucson. Surface dewpoints
over the central deserts at 2 am were mostly in the 40s, values a
bit below typical monsoon thresholds. Latest IR imagery showed
partly cloudy skies east of Globe but west of southern Gila County
skies were clear.
Model guidance has not changed much over the past day or two and
still calls for just a very gradual import of moisture from the
southeast over the weekend, with most of the convective activity to
remain focused over higher terrain areas to the east and southeast
of Phoenix - mostly across southeast Arizona from Tucson east. A
weak inverted trof slowly creeps westward with time and steering flow
becomes weakly east/southeast with speeds around 5-10kt. Deeper
moisture stays east of Phoenix through Sunday evening and CAPE
values over the higher terrain of southern Gila County still appear
minimal, mostly below 300 j/kg. As such, POPs over the lower deserts
today and Sunday will mostly stay in the single digits with just
slight chances expected across the higher terrain east of Phoenix.
High temps will stay above seasonal normals, and actually will climb
a degree or two Sunday as high pressure aloft starts to strengthen
again. By Sunday, we should see highs in Phoenix reach around 111
with hotter western deserts climbing to around 113. Still, these
values will stay mostly near or just below heat warning thresholds
based on our heat impact level data. Once again, rain over the
deserts this weekend is a slim bet but there remains a somewhat
better chance for some blowing dust to work into portions of the
central deserts, mainly the southeast Phoenix metropolitan area and
portions of northern/northwest Pinal county such as Casa Grande and
the I-10 corridor southeast of Phoenix.
The idea of keeping convection and associated rainfall mainly over
higher terrain areas east/southeast of Phoenix this weekend is
supported by various mesoscale models such as the WRK4KM and the
NMM6KM.
On Monday, progs agree that the upper high will continue to build to
our north and become centered near the Utah border over far
northcentral AZ, with a high center around 597DM. The orientation of
the high will allow for a much more monsoonal flow pattern to set up
with deeper easterly flow overspreading much of the lower deserts
and bringing pwat values over 1 inch into the far western deserts
and even into southeast CA. Still, the real deep lower level
moisture such as 850mb dewpoints over 10C remain east of Phoenix and
CAPE will still be minimal into the lower elevations. Due to the
more favorable steering flow and better moisture profile, we will
still call for slight chances of afternoon and evening thunderstorms
spreading into the south central deserts Monday, with chances
developing over the higher terrain east of Phoenix. With the very
warm air aloft, and the air over the western deserts still somewhat
on the dry side we can expect additional warming with high temps
reaching around 114 over the hotter western deserts Monday. Highs in
the Phoenix area will stay around 111. Overall, despite the warming
high temps will stay around but mostly a bit below excessive heat
warning thresholds Monday and we do not plan on issuing a heat watch
at this time.
Tuesday through Friday...Model guidance including NAEFS and GEFS
ensemble guidance continues to suggest that our flow pattern is
setting up in a standard monsoonal fashion, with the upper high
migrating towards the vicinity of the four corners, and a much
deeper and widespread southeast steering flow working its way over
the AZ deserts and even into southeast CA. Moisture continues to
work across the lower deserts and rainfall chances will increase
with slight chances developing to the lower Colorado River valley
and potentially into the deserts of southeast CA. We have raised
POPs over much of the CWA correspondingly, with chance numbers over
the higher terrain of southern Gila County and slight chances over
much of the southcentral deserts westward. High temperatures take a
slow decline day to day as humidity values rise.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
Gusty erratic winds and blowing dust from distant south and east AZ
storms will be possible this afternoon and early evening (after 00Z)
at Phoenix terminals. However, low confidence in exact spatial and
temporal coverage precludes mention in 18Z TAF. Outside of potential
storm outflows, winds will be on the light side, mainly aob 10 kts
throughout the TAF period, following typical diurnal trends. Few to
scattered high cirrus cloud layers this morning will become scattered
to broken mid-high cloud layers this afternoon/evening as a result of
debris clouds from distant thunderstorms.
Southeast California/Southwest Arizona including KIPL and KBLH:
Skies will remain mostly clear over both TAF sites. Winds will
remain out of the south at KBLH and out of the south to southeast at
KIPL, with speeds generally aob 10 kts accompanied by a few afternoon
gusts up to 15 to 20 kts.
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Monday through Friday...
Temperatures will start a gradual "cooling" trend, with highs on
Monday around 110-115F dropping into the 100-110F range by Friday.
Isolated thunderstorms are possible each afternoon/evening,
primarily over the higher terrain north and east of Phoenix on
Monday, and then over much of the desert southwest Tuesday through
Friday.
On Monday, given that conditions will remain dry in the lower levels
with minimum humidities generally between 10 and 20 percent, there
will be very little if any measurable rain. Mostly gusty erratic
winds and dry lightning will accompany storms potentially igniting
new fires or promoting the spread of existing fires.
Better chances for wetting rains is expected from Tuesday into
Friday as monsoon moisture levels increase over the region, with the
highest chances for rainfall still remaining over the higher terrain
of south-central AZ. Also accompanying the storms will be gusty
erratic winds and lightning. Minimum humidities during the Tuesday
through Friday period will rise into the 15-25 percent range, with
fair to good overnight recoveries.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
Visit us on Facebook...Twitter...and at weather.gov/phoenix
DISCUSSION...Vasquez/CB
AVIATION...Hernandez
FIRE WEATHER...Hernandez
Area Forecast Discussion
National Weather Service Flagstaff AZ
1005 AM MST SAT JUN 25 2016
.SYNOPSIS...Expect mainly dry and continued hot conditions heading
into the weekend, with a few showers or thunderstorms around and
east of Flagstaff to the White Mountains. Moisture will slowly
return by early next week as a more monsoonal type of circulation
develops, leading to increased shower and thunderstorm activity and
more seasonable temperatures.
&&
.Discussion...Updated POPS to expand slight chance of showers/
thunderstorms westward to around Flagstaff as satellite derived PW
is over 0.8 inches. Most of the moisture is in the mid levels so any
storms that do form will have the potential to produce strong gusty
winds.
&&
.PREV DISCUSSION ...Very dry air aloft covers most of Arizona as
westerly flow continues. The exception is over far eastern Arizona,
where a fairly obvious plume of monsoonal moisture persists. A s/wv
over western Montana will keep this plume where it is today, maybe
even push it a bit further east. Behind this s/wv, westerly flow
will relax Sunday and heading into next week.
Models show high pressure building and moving back west. This will
open the door for the monsoonal airmass to move back west and north
through much of next week. The flow pattern really starts to look
good later in the week as hghts fall and the high consolidates over
New Mexico. We kept with the previous thinking of slowly raising
pops each day from Sunday onward, while steadily pushing the monsoon
boundary westward and lowering temperatures each day.
&&
.AVIATION...For the 18Z Package...Expect widely scattered showers
and thunderstorms in the White Mountains region and isolated along
the Mogollon Rim today from 18Z to 02Z. Otherwise, expect VFR
conditions. Smoke downwind of area wildfires may impact local
visibility. Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Dry air aloft to cover most of northern Arizona
today, and limit limit shower and thunderstorm coverage to the
higher terrain in Apache county and along the Mogollon Rim. These
high based thunderstorms may produce erratic gusty winds.
Sunday through Wednesday...Additional mid level moisture begins to
move in from the south and southeast on Sunday and Monday as we
transition into a monsoonal flow pattern. High based storms should
be increasing in coverage, with the threat of strong outflow winds
expanding across the northland.
&&
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...MAS/Peterson
AVIATION...DL
FIRE WEATHER...DL
For Northern Arizona weather information visit
weather.gov/flagstaff
Area Forecast Discussion
National Weather Service Flagstaff AZ
1005 AM MST SAT JUN 25 2016
.SYNOPSIS...Expect mainly dry and continued hot conditions heading
into the weekend, with a few showers or thunderstorms around and
east of Flagstaff to the White Mountains. Moisture will slowly
return by early next week as a more monsoonal type of circulation
develops, leading to increased shower and thunderstorm activity and
more seasonable temperatures.
&&
.Discussion...Updated POPS to expand slight chance of showers/
thunderstorms westward to around Flagstaff as satellite derived PW
is over 0.8 inches. Most of the moisture is in the mid levels so any
storms that do form will have the potential to produce strong gusty
winds.
&&
.PREV DISCUSSION ...Very dry air aloft covers most of Arizona as
westerly flow continues. The exception is over far eastern Arizona,
where a fairly obvious plume of monsoonal moisture persists. A s/wv
over western Montana will keep this plume where it is today, maybe
even push it a bit further east. Behind this s/wv, westerly flow
will relax Sunday and heading into next week.
Models show high pressure building and moving back west. This will
open the door for the monsoonal airmass to move back west and north
through much of next week. The flow pattern really starts to look
good later in the week as hghts fall and the high consolidates over
New Mexico. We kept with the previous thinking of slowly raising
pops each day from Sunday onward, while steadily pushing the monsoon
boundary westward and lowering temperatures each day.
&&
.AVIATION...For the 18Z Package...Expect widely scattered showers
and thunderstorms in the White Mountains region and isolated along
the Mogollon Rim today from 18Z to 02Z. Otherwise, expect VFR
conditions. Smoke downwind of area wildfires may impact local
visibility. Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Dry air aloft to cover most of northern Arizona
today, and limit limit shower and thunderstorm coverage to the
higher terrain in Apache county and along the Mogollon Rim. These
high based thunderstorms may produce erratic gusty winds.
Sunday through Wednesday...Additional mid level moisture begins to
move in from the south and southeast on Sunday and Monday as we
transition into a monsoonal flow pattern. High based storms should
be increasing in coverage, with the threat of strong outflow winds
expanding across the northland.
&&
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...MAS/Peterson
AVIATION...DL
FIRE WEATHER...DL
For Northern Arizona weather information visit
weather.gov/flagstaff
Area Forecast Discussion
National Weather Service Tucson AZ
948 AM MST SAT JUN 25 2016
.SYNOPSIS...We now have enough moisture for isolated to scattered
showers and thunderstorms this weekend. A more favorable flow
regime will then provide increased coverage of showers and
thunderstorms Monday through Friday.
&&
.DISCUSSION...A chance of mainly afternoon and evening showers
and thunderstorms until further notice. Now for the details. The
12z KTWC morning sounding came up with another 1.4 inches
precipitable water value (like yesterday), however we`ve seen some
slight warming above 500mb. Nothing special, with conditional
instability pointing us toward areas that see more solar
insolation (heating from the sun). The axis of the remnant debris
could is stretching through Santa Cruz, Eastern Pima and Graham
counties with slow clearing. The easterly flow is deeper through
mid levels...but is also a little weaker as well. So, while we
have favorable vectors to get the cirrus shield out of the way of
storm development, the storms themselves aren`t going to be quite
as dynamic for the most part.
The exception, and favored area for development, will be along a
weak moisture convergence axis just west of Tucson southward into
Sonora, where we will also see plenty of sunshine. Our best storms
should be there, as well as areas along the international border
this afternoon. This evening, weaker outflow spreading through the
area with some weaker embedded convection in the debris will
spread across the area from the southeast.
Beyond today and tonight, please see the previous discussion
below for additional details.
&&
.AVIATION...VALID THRU 26/18Z.
Isolated to scattered -TSRA/-SHRA this afternoon into Sunday
morning. Cloud decks ranging from 10k- 15k ft msl. Surface wind
will generally be less than 10 kts into early Sunday morning.
However, surface wind this afternoon vicinity KSAD will be
wly/nwly at 12-16 kts with gusts to near 20 kts. Aviation
discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Expect isolated to scattered showers and
thunderstorms this weekend. Greater coverage of showers and
thunderstorms should then occur Monday through next Friday.
Otherwise, daytime minimum relative humidity values will generally
range from the mid teens to around 30 percent with fair to good
nighttime recovery. 20-foot winds this weekend as well as
Wednesday through Friday will be terrain driven at less than 15
mph. 20-foot winds Monday and Tuesday will generally be from the
east at 5-15 mph with gusts of 15-20 mph. The strongest speeds
Monday and Tuesday should prevail from shortly after sunrise into
the early afternoon hours.
&&
.PREV DISCUSSION...Strong high pressure aloft early this morning
was centered west of northern Baja California near 30N/125W.
Meanwhile, a closed upper low was centered over nern Montana, and
a broad upper low was centered just south of the Texas Big Bend
region.
The 25/00Z NAM/GFS/ECMWF/CMC and 25/03Z SREF all suggest that
precip coverage would decrease somewhat Sunday. However, only
slightly decreased PoPs are depicted in the official forecast for
Sunday afternoon/evening. Have again depicted patchy blowing dust
late Sunday afternoon and early Sunday evening for locales
northwest of Tucson.
25/00Z GFS/ECMWF/CMC were then in very good agreement with developing
a deeper easterly flow regime across southeast Arizona Monday into
Tuesday. This flow pattern is in response to strong high pressure
aloft becoming centered over southern Utah. At any rate, the
coverage of showers/tstms starting Monday should increase across the
area, and PoPs were raised somewhat to reflect this notion. The NAM
and CMC are suggesting that Monday afternoon/evening may potentially
be fairly active, as an inverted trough/weak closed upper low
approaches from the southeast.
Thereafter, high pressure aloft is progged to become centered over
the Four Corners region Wednesday, and then the upper high
eventually becomes centered further southeast over west Texas
Friday. Have noted that the ECMWF is markedly more robust with QPF
fields versus the GFS. The upshot is that a fairly light sely/sly
mid-level flow regime will maintain adequate moisture to support the
continuation of at least slight chance PoPs during the latter part
of next week.
High temps for the Tucson metro area and locales west-to-northwest
of Tucson will be near normal. However, daytime temps for locales
east-to-south of Tucson, including Safford, Douglas and Nogales will
average a few degs below normal thru much of this forecast period.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Meyer/Francis
Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
AFDPSR
Area Forecast Discussion
National Weather Service Phoenix AZ
830 AM MST SAT JUN 25 2016
.SYNOPSIS...
A very warm air mass will keep temperatures above normal through at
least the first half of next week. A gradual increase in moisture
will seep into portions of Arizona later this week and into next
week leading to a threat for showers and thunderstorms. Rainfall
will initially be limited to high terrain areas, then finally move
towards lower desert communities as we move into next week.
&&
.DISCUSSION...
Woohoo! The low level monsoon moisture boundary (MMB) finally made
inroads into southeast AZ yesterday for the first time this year,
and showed gains this morning from the weather balloon soundings.
The monsoon moisture boundary as defined in a Sept 1993 paper by the
same author, "Weak Upper-Level Divergence and Its Role in Organizing
Mesoscale Convective Storms along the ARIZONA MONSOON MOISTURE
BOUNDARY" is basically the amount of boundary layer moisture
threshold point where C.A.P.E. first develops on an average
warm season weather balloon sounding in AZ, given soundings change
very little during this 3 month warm season/summer. 850-800 mb
dewpoint minimally needs to be 8 degrees C, and for a bonus 700 mb
dewpoints 4 degrees C. Together this points to an even deeper
leading edge monsoon moisture boundary.
This morning the Tucson balloon sounding measured an 800 mb
dewpoint of 8 degrees C and at 700 mb 6 deg C. This MMB also
extended from the White mountains in far east central AZ, southwest
through Tucson and Nogales. Correspondingly, and no surprise,
convective trigger temperatures in southeast AZ were as follows:
Tucson 101 deg F with a high fcst of 101 deg, Douglas 89 deg F with
a high fcst of 93, Globe/Miami 89 with a high fcst of 98, and Casa
Grande 106 with a high fcst of 106.
Additionally, water vapor and IR imagery show a stream of
moisture/cloudiness emanating from northwest Mexico, through
Southeast AZ, and into northwest New Mexico. This pattern will
remain quasi-stationary through Monday with a few weak 300/250 mb
perturbations, bursts of accelerating wind, and some weak difluence
to unweight the atmosphere to provide support for deep boundary
layer, minimal C.A.P.E. convective threats in southeast AZ.
Weather balloon soundings for the deserts and mountains outside of
southeast AZ, or the remainder of our Forecast Area are
operationally too dry for convective threats. However, there
could be an outflow boundary emanating from southeast AZ late in the
day or early evening with a threat of dust between Phoenx and
Casa Grande.
Current forecasts which focus any convective threats over the
distant mountains east and southeast of Phoenix this weekend look
ok for now. No updates planned.
.PREVIOUS DISCUSSION...453 AM MST...
Early this morning, in the wake of troffing that passed by well to
our north, flow aloft over Arizona had turned to the west and
southwest as seen in the recent 00z AZ raobs as well as upper plot
data. Moisture, at least over eastern Arizona, remained a bit
elevated with a pwat of 1.16 inches at Tucson. Surface dewpoints
over the central deserts at 2 am were mostly in the 40s, values a
bit below typical monsoon thresholds. Latest IR imagery showed
partly cloudy skies east of Globe but west of southern Gila County
skies were clear.
Model guidance has not changed much over the past day or two and
still calls for just a very gradual import of moisture from the
southeast over the weekend, with most of the convective activity to
remain focused over higher terrain areas to the east and southeast
of Phoenix - mostly across southeast Arizona from Tucson east. A
weak inverted trof slowly creeps westward with time and steering flow
becomes weakly east/southeast with speeds around 5-10kt. Deeper
moisture stays east of Phoenix through Sunday evening and CAPE
values over the higher terrain of southern Gila County still appear
minimal, mostly below 300 j/kg. As such, POPs over the lower deserts
today and Sunday will mostly stay in the single digits with just
slight chances expected across the higher terrain east of Phoenix.
High temps will stay above seasonal normals, and actually will climb
a degree or two Sunday as high pressure aloft starts to strengthen
again. By Sunday, we should see highs in Phoenix reach around 111
with hotter western deserts climbing to around 113. Still, these
values will stay mostly near or just below heat warning thresholds
based on our heat impact level data. Once again, rain over the
deserts this weekend is a slim bet but there remains a somewhat
better chance for some blowing dust to work into portions of the
central deserts, mainly the southeast Phoenix metropolitan area and
portions of northern/northwest Pinal county such as Casa Grande and
the I-10 corridor southeast of Phoenix.
The idea of keeping convection and associated rainfall mainly over
higher terrain areas east/southeast of Phoenix this weekend is
supported by various mesoscale models such as the WRK4KM and the
NMM6KM.
On Monday, progs agree that the upper high will continue to build to
our north and become centered near the Utah border over far
northcentral AZ, with a high center around 597DM. The orientation of
the high will allow for a much more monsoonal flow pattern to set up
with deeper easterly flow overspreading much of the lower deserts
and bringing pwat values over 1 inch into the far western deserts
and even into southeast CA. Still, the real deep lower level
moisture such as 850mb dewpoints over 10C remain east of Phoenix and
CAPE will still be minimal into the lower elevations. Due to the
more favorable steering flow and better moisture profile, we will
still call for slight chances of afternoon and evening thunderstorms
spreading into the south central deserts Monday, with chances
developing over the higher terrain east of Phoenix. With the very
warm air aloft, and the air over the western deserts still somewhat
on the dry side we can expect additional warming with high temps
reaching around 114 over the hotter western deserts Monday. Highs in
the Phoenix area will stay around 111. Overall, despite the warming
high temps will stay around but mostly a bit below excessive heat
warning thresholds Monday and we do not plan on issuing a heat watch
at this time.
Tuesday through Friday...Model guidance including NAEFS and GEFS
ensemble guidance continues to suggest that our flow pattern is
setting up in a standard monsoonal fashion, with the upper high
migrating towards the vicinity of the four corners, and a much
deeper and widespread southeast steering flow working its way over
the AZ deserts and even into southeast CA. Moisture continues to
work across the lower deserts and rainfall chances will increase
with slight chances developing to the lower Colorado River valley
and potentially into the deserts of southeast CA. We have raised
POPs over much of the CWA correspondingly, with chance numbers over
the higher terrain of southern Gila County and slight chances over
much of the southcentral deserts westward. High temperatures take a
slow decline day to day as humidity values rise.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
Weak sfc pressure gradients to keep winds on the light side, mainly
aob 10 kts through the taf period, mostly following typical diurnal
trends. Few-sct high cirrus cloud layers this morning to give way to
sct-bkn mid-high cloud layers on this aft/evening as debris clouds
from distant thunderstorms to the south and east spread over the PHX
area. There is also an outside chance that outflows from these storms
could affect one or more of the PHX area terminals, with gusty winds
and blowing dust, but confidence is too low to include them in the
tafs at this time.
Southeast California/Southwest Arizona including KIPL and KBLH:
Mainly clear skies to prevail through the taf period. Winds to
remain mainly out of the south at KBLH and mainly follow typical
diurnal trends at KIPL.
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Monday through Friday...
Temperatures will start a gradual "cooling" trend, with highs on
Monday around 110-115F dropping into the 100-110F range by Friday.
Isolated thunderstorms are possible each afternoon/evening,
primarily over the higher terrain north and east of Phoenix on
Monday, and then over much of the desert southwest Tuesday through
Friday.
On Monday, given that conditions will remain dry in the lower levels
with minimum humidities generally between 10 and 20 percent, there
will be very little if any measurable rain. Mostly gusty erratic
winds and dry lightning will accompany storms potentially igniting
new fires or promoting the spread of existing fires.
Better chances for wetting rains is expected from Tuesday into
Friday as monsoon moisture levels increase over the region, with the
highest chances for rainfall still remaining over the higher terrain
of south-central AZ. Also accompanying the storms will be gusty
erratic winds and lightning. Minimum humidities during the Tuesday
through Friday period will rise into the 15-25 percent range, with
fair to good overnight recoveries.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
Visit us on Facebook...Twitter...and at weather.gov/phoenix
DISCUSSION...Vasquez/CB
AVIATION...Percha/Kuhlman
FIRE WEATHER...Hernandez
Area Forecast Discussion
National Weather Service Phoenix AZ
453 AM MST SAT JUN 25 2016
.SYNOPSIS...
A very warm air mass will keep temperatures above normal through at
least the first half of next week. A gradual increase in moisture
will seep into portions of Arizona later this week and into next
week leading to a threat for showers and thunderstorms. Rainfall
will initially be limited to high terrain areas, then finally move
towards lower desert communities as we move into next week.
&&
.DISCUSSION...
Early this morning, in the wake of troffing that passed by well to
our north, flow aloft over Arizona had turned to the west and
southwest as seen in the recent 00z AZ raobs as well as upper plot
data. Moisture, at least over eastern Arizona, remained a bit
elevated with a pwat of 1.16 inches at Tucson. Surface dewpoints
over the central deserts at 2 am were mostly in the 40s, values a
bit below typical monsoon thresholds. Latest IR imagery showed
partly cloudy skies east of Globe but west of southern Gila County
skies were clear.
Model guidance has not changed much over the past day or two and
still calls for just a very gradual import of moisture from the
southeast over the weekend, with most of the convective activity to
remain focused over higher terrain areas to the east and southeast
of Phoenix - mostly across southeast Arizona from Tucson east. A
weak inverted trof slowly creeps westward with time and steering flow
becomes weakly east/southeast with speeds around 5-10kt. Deeper
moisture stays east of Phoenix through Sunday evening and CAPE
values over the higher terrain of southern Gila County still appear
minimal, mostly below 300 j/kg. As such, POPs over the lower deserts
today and Sunday will mostly stay in the single digits with just
slight chances expected across the higher terrain east of Phoenix.
High temps will stay above seasonal normals, and actually will climb
a degree or two Sunday as high pressure aloft starts to strengthen
again. By Sunday, we should see highs in Phoenix reach around 111
with hotter western deserts climbing to around 113. Still, these
values will stay mostly near or just below heat warning thresholds
based on our heat impact level data. Once again, rain over the
deserts this weekend is a slim bet but there remains a somewhat
better chance for some blowing dust to work into portions of the
central deserts, mainly the southeast Phoenix metropolitan area and
portions of northern/northwest Pinal county such as Casa Grande and
the I-10 corridor southeast of Phoenix.
The idea of keeping convection and associated rainfall mainly over
higher terrain areas east/southeast of Phoenix this weekend is
supported by various mesocale models such as the WRK4KM and the
NMM6KM.
On Monday, progs agree that the upper high will continue to build to
our north and become centered near the Utah border over far
northcentral AZ, with a high center around 597DM. The orientation of
the high will allow for a much more monsoonal flow pattern to set up
with deeper easterly flow overspreading much of the lower deserts
and bringing pwat values over 1 inch into the far western deserts
and even into southeast CA. Still, the real deep lower level
moisture such as 850mb dewpoints over 10C remain east of Phoenix and
CAPE will still be minimal into the lower elevations. Due to the
more favorable steering flow and better moisture profile, we will
still call for slight chances of afternoon and evening thunderstorms
spreading into the south central deserts Monday, with chances
developing over the higher terrain east of Phoenix. With the very
warm air aloft, and the air over the western deserts still somewhat
on the dry side we can expect additional warming with high temps
reaching around 114 over the hotter western deserts Monday. Highs in
the Phoenix area will stay around 111. Overall, despite the warming
high temps will stay around but mostly a bit below excessive heat
warning thresholds Monday and we do not plan on issuing a heat watch
at this time.
Tuesday through Friday...Model guidance including NAEFS and GEFS
ensemble guidance continues to suggest that our flow pattern is
setting up in a standard monsoonal fashion, with the upper high
migrating towards the vicinity of the four corners, and a much
deeper and widespread southeast steering flow working its way over
the AZ deserts and even into southeast CA. Moisture continues to
work across the lower deserts and rainfall chances will increase
with slight chances developing to the lower Colorado River valley
and potentially into the deserts of southeast CA. We have raised
POPs over much of the CWA correspondingly, with chance numbers over
the higher terrain of southern Gila County and slight chances over
much of the southcentral deserts westward. High temperatures take a
slow decline day to day as humidity values rise.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
Weak sfc pressure gradients to keep winds on the light side, mainly
aob 10 kts through the taf period, mostly following typical diurnal
trends. Few-sct high cirrus cloud layers this morning to give way to
sct-bkn mid-high cloud layers on this aft/evening as debris clouds
from distant thunderstorms to the south and east spread over the PHX
area. There is also an outside chance that outflows from these storms
could affect one or more of the PHX area terminals, with gusty winds
and blowing dust, but confidence is too low to include them in the
tafs at this time.
Southeast California/Southwest Arizona including KIPL and KBLH:
Mainly clear skies to prevail through the taf period. Winds to
remain mainly out of the south at KBLH and mainly follow typical
diurnal trends at KIPL.
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Monday through Friday...
Temperatures will start a gradual "cooling" trend, with highs on
Monday around 110-115F dropping into the 100-110F range by Friday.
Isolated thunderstorms are possible each afternoon/evening,
primarily over the higher terrain north and east of Phoenix on
Monday, and then over much of the desert southwest Tuesday through
Friday.
On Monday, given that conditions will remain dry in the lower levels
with minimum humidities generally between 10 and 20 percent, there
will be very little if any measurable rain. Mostly gusty erratic
winds and dry lightning will accompany storms potentially igniting
new fires or promoting the spread of existing fires.
Better chances for wetting rains is expected from Tuesday into
Friday as monsoon moisture levels increase over the region, with the
highest chances for rainfall still remaining over the higher terrain
of south-central AZ. Also accompanying the storms will be gusty
erratic winds and lightning. Minimum humidities during the Tuesday
through Friday period will rise into the 15-25 percent range, with
fair to good overnight recoveries.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
Visit us on Facebook...Twitter...and at weather.gov/phoenix
DISCUSSION...CB
AVIATION...Percha/Kuhlman
FIRE WEATHER...Hernandez
Area Forecast Discussion
National Weather Service Phoenix AZ
453 AM MST SAT JUN 25 2016
.SYNOPSIS...
A very warm air mass will keep temperatures above normal through at
least the first half of next week. A gradual increase in moisture
will seep into portions of Arizona later this week and into next
week leading to a threat for showers and thunderstorms. Rainfall
will initially be limited to high terrain areas, then finally move
towards lower desert communities as we move into next week.
&&
.DISCUSSION...
Early this morning, in the wake of troffing that passed by well to
our north, flow aloft over Arizona had turned to the west and
southwest as seen in the recent 00z AZ raobs as well as upper plot
data. Moisture, at least over eastern Arizona, remained a bit
elevated with a pwat of 1.16 inches at Tucson. Surface dewpoints
over the central deserts at 2 am were mostly in the 40s, values a
bit below typical monsoon thresholds. Latest IR imagery showed
partly cloudy skies east of Globe but west of southern Gila County
skies were clear.
Model guidance has not changed much over the past day or two and
still calls for just a very gradual import of moisture from the
southeast over the weekend, with most of the convective activity to
remain focused over higher terrain areas to the east and southeast
of Phoenix - mostly across southeast Arizona from Tucson east. A
weak inverted trof slowly creeps westward with time and steering flow
becomes weakly east/southeast with speeds around 5-10kt. Deeper
moisture stays east of Phoenix through Sunday evening and CAPE
values over the higher terrain of southern Gila County still appear
minimal, mostly below 300 j/kg. As such, POPs over the lower deserts
today and Sunday will mostly stay in the single digits with just
slight chances expected across the higher terrain east of Phoenix.
High temps will stay above seasonal normals, and actually will climb
a degree or two Sunday as high pressure aloft starts to strengthen
again. By Sunday, we should see highs in Phoenix reach around 111
with hotter western deserts climbing to around 113. Still, these
values will stay mostly near or just below heat warning thresholds
based on our heat impact level data. Once again, rain over the
deserts this weekend is a slim bet but there remains a somewhat
better chance for some blowing dust to work into portions of the
central deserts, mainly the southeast Phoenix metropolitan area and
portions of northern/northwest Pinal county such as Casa Grande and
the I-10 corridor southeast of Phoenix.
The idea of keeping convection and associated rainfall mainly over
higher terrain areas east/southeast of Phoenix this weekend is
supported by various mesocale models such as the WRK4KM and the
NMM6KM.
On Monday, progs agree that the upper high will continue to build to
our north and become centered near the Utah border over far
northcentral AZ, with a high center around 597DM. The orientation of
the high will allow for a much more monsoonal flow pattern to set up
with deeper easterly flow overspreading much of the lower deserts
and bringing pwat values over 1 inch into the far western deserts
and even into southeast CA. Still, the real deep lower level
moisture such as 850mb dewpoints over 10C remain east of Phoenix and
CAPE will still be minimal into the lower elevations. Due to the
more favorable steering flow and better moisture profile, we will
still call for slight chances of afternoon and evening thunderstorms
spreading into the south central deserts Monday, with chances
developing over the higher terrain east of Phoenix. With the very
warm air aloft, and the air over the western deserts still somewhat
on the dry side we can expect additional warming with high temps
reaching around 114 over the hotter western deserts Monday. Highs in
the Phoenix area will stay around 111. Overall, despite the warming
high temps will stay around but mostly a bit below excessive heat
warning thresholds Monday and we do not plan on issuing a heat watch
at this time.
Tuesday through Friday...Model guidance including NAEFS and GEFS
ensemble guidance continues to suggest that our flow pattern is
setting up in a standard monsoonal fashion, with the upper high
migrating towards the vicinity of the four corners, and a much
deeper and widespread southeast steering flow working its way over
the AZ deserts and even into southeast CA. Moisture continues to
work across the lower deserts and rainfall chances will increase
with slight chances developing to the lower Colorado River valley
and potentially into the deserts of southeast CA. We have raised
POPs over much of the CWA correspondingly, with chance numbers over
the higher terrain of southern Gila County and slight chances over
much of the southcentral deserts westward. High temperatures take a
slow decline day to day as humidity values rise.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
Weak sfc pressure gradients to keep winds on the light side, mainly
aob 10 kts through the taf period, mostly following typical diurnal
trends. Few-sct high cirrus cloud layers this morning to give way to
sct-bkn mid-high cloud layers on this aft/evening as debris clouds
from distant thunderstorms to the south and east spread over the PHX
area. There is also an outside chance that outflows from these storms
could affect one or more of the PHX area terminals, with gusty winds
and blowing dust, but confidence is too low to include them in the
tafs at this time.
Southeast California/Southwest Arizona including KIPL and KBLH:
Mainly clear skies to prevail through the taf period. Winds to
remain mainly out of the south at KBLH and mainly follow typical
diurnal trends at KIPL.
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Monday through Friday...
Temperatures will start a gradual "cooling" trend, with highs on
Monday around 110-115F dropping into the 100-110F range by Friday.
Isolated thunderstorms are possible each afternoon/evening,
primarily over the higher terrain north and east of Phoenix on
Monday, and then over much of the desert southwest Tuesday through
Friday.
On Monday, given that conditions will remain dry in the lower levels
with minimum humidities generally between 10 and 20 percent, there
will be very little if any measurable rain. Mostly gusty erratic
winds and dry lightning will accompany storms potentially igniting
new fires or promoting the spread of existing fires.
Better chances for wetting rains is expected from Tuesday into
Friday as monsoon moisture levels increase over the region, with the
highest chances for rainfall still remaining over the higher terrain
of south-central AZ. Also accompanying the storms will be gusty
erratic winds and lightning. Minimum humidities during the Tuesday
through Friday period will rise into the 15-25 percent range, with
fair to good overnight recoveries.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
Visit us on Facebook...Twitter...and at weather.gov/phoenix
DISCUSSION...CB
AVIATION...Percha/Kuhlman
FIRE WEATHER...Hernandez
Area Forecast Discussion
National Weather Service Flagstaff AZ
445 AM MST SAT JUN 25 2016
.SYNOPSIS...Expect mainly dry and continued hot conditions heading
into the weekend, with a few showers or thunderstorms to the east of
Flagstaff. Moisture will slowly return by early next week as a more
monsoonal type of circulation develops, leading to increased shower
and thunderstorm activity and more seasonable temperatures.
&&
.DISCUSSION...Very dry air aloft covers most of Arizona as westerly
flow continues. The exception is over far eastern Arizona, where a
fairly obvious plume of monsoonal moisture persists. A s/wv over
western Montana will keep this plume where it is today, maybe even
push it a bit further east. Behind this s/wv, westerly flow will
relax Sunday and heading into next week.
Models show high pressure building and moving back west. This will
open the door for the monsoonal airmass to move back west and north
through much of next week. The flow pattern really starts to look
good later in the week as hghts fall and the high consolidates over
New Mexico. We kept with the previous thinking of slowly raising
pops each day from Sunday onward, while steadily pushing the monsoon
boundary westward and lowering temperatures each day.
&&
.AVIATION...For the 12Z Package...Expect widely scattered showers
and thunderstorms east of a KPAN-Krqe line btwn 18Z Sat -02z Sun.
Otherwise, expect VFR conditions. Smoke downwind of area wildfires
may impact visibility at times. Aviation discussion not updated for
TAF amendments.
&&
.FIRE WEATHER...Dry air aloft to cover most of northern Arizona
today, and limit limit shower and thunderstorm coverage to the
higher terrain in Apache county. These high based thunderstorms may
produce erratic gusty winds.
Sunday through Wednesday...Additional mid level moisture begins to
move in from the south and southeast on Sunday and Monday as we
transition into a monsoonal flow pattern. High based storms should
be increasing in coverage, with the threat of strong outflow winds
expanding across the northland.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...Peterson
AVIATION...DL
FIRE WEATHER...DL
For Northern Arizona weather information visit
weather.gov/flagstaff
Area Forecast Discussion
National Weather Service Tucson AZ
415 AM MST SAT JUN 25 2016
.SYNOPSIS...Isolated to scattered showers and thunderstorms will
occur mainly east and south of Tucson this weekend. A more favorable
flow regime will then provide increased coverage of showers and
thunderstorms Monday through Friday. High temperatures will be near
normal or a few degrees below normal.
&&
.DISCUSSION...Strong high pressure aloft early this morning was
centered west of northern Baja California near 30N/125W. Meanwhile,
a closed upper low was centered over nern Montana, and a broad upper
low was centered just south of the Texas Big Bend region. IR/water
vapor satellite imagery depicted mostly cloudy to cloudy skies from
Tucson east to the New Mexico border, and clear skies across western
sections of this forecast area. Isolated showers producing mostly
virga has occurred much of the overnight hours across Greenlee,
Graham and Cochise counties east of Tucson.
Several HRRR solutions have been similar with depicting the ongoing
very light precip area to either expand or move westward toward the
Tucson metro area and further southward into Santa Cruz County later
this morning. Given the light generally swly mid-level flow regime
across the area, am not necessarily inclined to agree with these
solutions.
However, another plausible scenario for the development of showers
and thunderstorms later today would be adjacent the boundary
separating the deeper moisture from Tucson eastward, and the drier
air across western sections as depicted via water vapor imagery.
At any rate, have maintained isolated to scattered coverage of
showers and thunderstorms across much of the area into this evening.
The best precip chances will be east-to-south of Tucson. Given the
fairly dry near-surface environment, have also maintained patchy
blowing dust late this afternoon and early this evening essentially
along the I-10 corridor from Tucson nwwd into south central Pinal
County. The 25/00Z NAM/GFS/ECMWF/CMC and 25/03Z SREF all suggest
that precip coverage would decrease somewhat Sunday. However, only
slightly decreased PoPs are depicted in the official forecast for
Sunday afternoon/evening. Have again depicted patchy blowing dust
late Sunday afternoon and early Sunday evening for locales northwest
of Tucson.
25/00Z GFS/ECMWF/CMC were then in very good agreement with developing
a deeper easterly flow regime across southeast Arizona Monday into
Tuesday. This flow pattern is in response to strong high pressure
aloft becoming centered over southern Utah. At any rate, the
coverage of showers/tstms starting Monday should increase across the
area, and PoPs were raised somewhat to reflect this notion. The NAM
and CMC are suggesting that Monday afternoon/evening may potentially
be fairly active, as an inverted trough/weak closed upper low
approaches from the southeast.
Thereafter, high pressure aloft is progged to become centered over
the Four Corners region Wednesday, and then the upper high
eventually becomes centered further southeast over west Texas
Friday. Have noted that the ECMWF is markedly more robust with QPF
fields versus the GFS. The upshot is that a fairly light sely/sly
mid-level flow regime will maintain adequate moisture to support the
continuation of at least slight chance PoPs during the latter part
of next week.
High temps for the Tucson metro area and locales west-to-northwest
of Tucson will be near normal. However, daytime temps for locales
east-to-south of Tucson, including Safford, Douglas and Nogales will
average a few degs below normal thru much of this forecast period.
&&
.AVIATION...VALID THRU 26/12Z.
Isolated -SHRA this morning east of KTUS, then isolated to scattered
-TSRA/-SHRA mainly east-to-south of KTUS this afternoon into Sunday
morning. Otherwise, mostly clear skies will prevail west of KTUS
thru the period. KTUS vicinity east and south expect cloud decks
ranging from 10k-15k ft msl. Surface wind will generally be less
than 10 kts into early Sunday morning. However, surface wind this
afternoon vicinity KSAD will be wly/nwly at 12-16 kts with gusts to
near 20 kts. Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Expect isolated to scattered showers and
thunderstorms mainly east and south of Tucson this weekend. Greater
coverage of showers and thunderstorms should then occur Monday
through next Friday. Otherwise, daytime minimum relative humidity
values will generally range from the mid teens to around 30 percent
with fair to good nighttime recovery. 20-foot winds this weekend as
well as Wednesday through Friday will be terrain driven at less than
15 mph. 20-foot winds Monday and Tuesday will generally be from
the east at 5-15 mph with gusts of 15-20 mph. The strongest speeds
Monday and Tuesday should prevail from shortly after sunrise into
the early afternoon hours.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
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Francis