Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 06/29/16
Area Forecast Discussion
National Weather Service Phoenix AZ
805 PM MST TUE JUN 28 2016
.SYNOPSIS...
High pressure will move somewhat north and east of Arizona this week
allowing warm temperatures to prevail, but also bring a couple of
weather disturbances through the state. An increase in monsoon
moisture will accompany these weather systems, providing a threat of
afternoon and evening showers and thunderstorms the remainder of
week.
&&
.DISCUSSION...
Evening objective analysis depicted several low amplitude waves
captured within easterly flow through the SW Conus with the most
notable vorticity center through eastern New Mexico. 00Z KTWC
sounding sampled a nice looking 10 g/kg mixing ratio through the
boundary layer with little inhibition while KPSR showed 8 g/kg with
more capping around the H7 layer. Despite the MLcape near 500 J/kg
in a weakly capped environment allowing scattered deep convection
surround the forecast area, distinct subsidence more downstream from
ascent structures have caused much of storms over SE AZ and northern
AZ to fizzle.
However, more organized storms have materialized through eastern AZ
and activity continues to percolate through Gila county. Numerous
weak outflow boundaries were converging through the lower elevations
of central AZ likely modifying the environment. In addition,
easterly steering flow through the H7-H5 layer should also advect a
lobe of better midlevel moisture towards the forecast area. Thus,
feel activity will continue later into the evening and overnight
hours associated with shortwave activity. Have made some minor
adjustment to pops based on this analysis.
&&
.PREVIOUS DISCUSSION...
/305 PM MST TUE JUN 28 2016/
Tonight through Saturday...
Another and perhaps stronger upper level disturbance is forecast to
move from just off the central Baja west coast tonight, into
southern AZ late Wednesday afternoon. Interesting is the MOS precip
guidance is forecasting a higher probability of precipitation over
the south central AZ, including Phoenix Wednesday evening.
More recognizable upper level disturbances, like those currently
seen on water vapor imagery 650 miles southwest of San Diego, are
forecast to move into southern AZ Thu and Fri. Timing of these
disturbances are uncertain, and with the monsoon moisture in place,
a broad brush chance approach to afternoon and evening thunderstorms
is perhaps the best approach for now. The threat of tstms will be
primarily confined to portions of southwest and south central AZ for
the tonight through Saturday period.
Sunday through Tuesday...
Models are forecasting a somewhat airmass to overspread our forecast
area, southeast CA to south central AZ, from the west this period.
Although drier air pushes into southeast CA and the Colorado River
Valley, south central and southeast AZ will still hang on to some
remnant moisture. The monsoon moisture boundary retreats east
into the far southeast corner of AZ Mon and Tue.
However perhaps more importantly Monday through Wednesday is a major
adjustment in the upper level flow pattern. Winds at and above 300
mb become broadly anti-cyclonic, devoid of disturbances, and
certainly imply a very stable subsident airmass that could kill the
threat of afternoon/evening high elevation mountain storms.
Therefore this period will be a quiet one, meaning mostly clear
skies, warmer afternoon temperatures, with just a very slight chance
of an afternoon mountain thunderstorms in southern Gila County
bordering the White Mountains.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
Converging outflow boundaries and lift from waves approaching from
the east should allow thunderstorms to develop east of terminal
sites, and move towards/through the metro during the late evening
hours. Somewhat lower confidence in coverage of actual storms near
terminal sites, but shifting outflow winds from an E/NE direction
seem more likely. Periods of variable directions are also probable
after storms/outflow pass until a predominant east flow develops
tonight. Cigs will remain in a 10K ft range with/around these
storms.
Probability and coverage of storms appears even better late
Wednesday afternoon and evening with more direct impact likely for
terminals. Morning and early afternoon hours should remain quiet
with higher cloud decks, light easterly winds, and minimal to no
aviation impacts.
Southeast California/Southwest Arizona including KIPL and KBLH:
Little aviation impacts through Wednesday afternoon with storms
remaining well east of SE CA. While surface winds will favor a south
and southeasterly direction, outflow boundaries from distant storms
may cause abrupt wind shifts, or variable winds overnight.
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Thursday through Tuesday...
Enhanced humidities and storm chances will continue into Saturday.
Humidities will trend down substantially Sunday and Monday. In fact,
minimum humidities on the low deserts will be near 10 percent by
Monday. Similarly, overnight recovery will trend down to only fair.
Thunderstorm chances will be confined to the higher terrain of south-
central AZ Sun-Tue and be only slight. Apart from strong erratic
winds associated with thunderstorms, southerly breeziness can be
expected over southwest AZ and southeast CA Thu-Sat(less so over
south-central AZ). Winds will favor southwesterly directions next
week.
&&
.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...MO/Vasquez
AVIATION...MO
FIRE WEATHER...AJ
[top]
Area Forecast Discussion
National Weather Service Tucson AZ
718 PM MST TUE JUN 28 2016
.SYNOPSIS...Scattered showers and thunderstorms will occur through
tonight, with the favored areas south of Tucson and across the White
Mountains. Increasing moisture and a favorable flow regime will then
provide even greater coverage of showers and thunderstorms Wednesday
through Friday. A drying trend will then limit thunderstorms to
mainly near the New Mexico border by early next week.
&&
.UPDATE...Ran a quick update to the forecast based on latest runs of
the HRRR which has been rather consistent on a rim shot to move
across the area during the overnight hours. Will continue to
monitor.
&&
.DISCUSSION...Visible satellite imagery and KEMX WSR-88D showed
isolated to scattered convection this afternoon, mainly south and
west of I-10. So far the storms seem to be relatively tame, since
they are being sheared apart by low level easterly flow and upper
level southwesterly flow. It`s still feeling soupy out there with
sfc dewpoints holding steady in the 50s. 28/18z CIRA LPW indicated
the bulk of moisture was located near the international border and
across the western half of Pima County. Not as much activity as
anticipated over the White Mountains, but the latest runs of the
HRRR/WRFEMS are hinting at convection developing over that area
later on this evening, so there`s still time. Overall, it still
looks like scattered showers and thunderstorms will continue into
this evening, with isolated activity into the overnight hours.
The 28/12Z runs of the GFS/ECMWF remain in very good agreement
through at least the first part of the holiday weekend. The
anticipation is for an upswing in convective activity starting
tomorrow, with a focus on Thursday into Friday especially. High
pressure aloft currently located near the preferred Four Corners
region will remain quasi-stationary through tomorrow, with a shift
toward the east and southeast through the end of the work week. In
response, expect upper level flow to becoming increasingly
southeasterly and then southerly, which will really aid in ramping
up our moisture in the form of a Gulf surge. As such, wouldn`t be
surprised to see sfc dewpoints jump into the mid to upper 60s as
early as Wednesday night into Thursday morning. In addition, the
GFS/NAM indicate PWAT will jump to between 1.6 and 2 inches by
00Z Friday, with the highest values across western Pima County.
Thereafter, PWAT values look to drop to around 1.25 inches by 12z
Saturday, and continue to decrease into early next week as we lose
our monsoonal flow and a weak upper ridge/westerly flow develops
over the southwestern deserts. This will shut us down for a few days
with regard to convection, with the exception being areas adjacent
to the NM border and across the mountains. The GFS then tries to
reconsolidate high pressure over the four corners while the ECMWF
maintains westerly flow. As such, have continued with just slight
chance PoPs for eastern zones at the end of the forecast period. We
will also have to keep an eye on the tropics, as both the GFS/ECMWF
bring a system southwest of the Baja tip late next week. Something
to watch.
Expect a slow decrease in daytime temperatures through Friday, when
highs will top out 5-10 degrees below normal. We will then warm
right back up to normal levels by Sunday into early next week.
&&
.AVIATION...VALID THRU 30/00Z.
Scattered showers and thunderstorms will be in and around the
terminals through 29/08Z. KTUS, KDUG, and KOLS have the best chance
of seeing activity. VFR conditions will be the rule, however, brief
MVFR conditions in heavy rainfall are possible. Additionally, wind
gusts upwards of 30 kts will be possible in and around the strongest
storms. Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...With plenty of moisture and instability we
will have daily rounds of scattered showers and thunderstorms
through Friday. The strongest storms will be capable of very strong
winds and heavy downpours especially during the mid afternoon to
early evening hours. Moisture will diminish across the region
Saturday onward resulting in a decrease in the amount of convection
each day. By Monday any isolated convection will be limited to the
mountains near the eastern border and over the White Mountains.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
650 PM PDT TUE JUN 28 2016
Updated Aviation Discussion
.SYNOPSIS...
A slight chance of thunderstorms and showers into this evening for
Ventura and Los Angeles...mainly in the mountains and deserts.
Above normal temperatures will occur into next week with a cooling
trend for this weekend. An overnight coastal marine layer will
persist into next week. The weekend should see the high exit...
but may roll back in by Monday for a warming trend.
&&
.SHORT TERM...(TDY-FRI)
Mid and high level moisture continues to stream into the area this
afternoon. It`s still very dry at lower levels and so far we`ve
mostly just seen a few spits of light rain, mainly mtns and
Antelope Valley. The clouds have moderated the temperatures a bit,
especially in those same areas. Still a small chance of a shower
or tstorm across the interior this afternoon and evening, though
main threat would be gusty winds and dry lightning.
Along the coast a shallow marine lyr continues to hug the coast,
mainly west of malibu and south of Pt Conception. Unless the
mid and high clouds thicken up over the coast tonight and disrupt
the marine lyr it`s likely we`ll see a very similar coverage
pattern again Wednesday with dense fog likely in some areas.
With less moisture aloft tomorrow most areas that saw cooling
today will see a rebound of temps back to near Monday`s levels.
Elsewhere similar to slightly cooler.
The ridge starts to break down Thu and especially Friday as a
trough moves into the Pac NW. Coast and valleys will see a little
cooling Thu with increasing onshore flow, then additional and more
widespread cooling Friday as the trough deepens. Low clouds may be
sneaking into the valleys by then. Highs should return to near
normal levels.
.LONG TERM...(SAT-TUE)
The trough is expected to move east by Sunday and at least inland
areas should start to see a slight warmup Sunday afternoon. Models
in general agreement through early next week showing the ridge
at least trying to rebuild over the area, though not nearly as
strong as we saw it this week. ECMWF lags a bit with the warmup as
it keeps some troughing going across northern CA. Current forecast
is a blend of the two solutions, thus some warming but not as much
as the GFS is showing.
&&
.AVIATION...29/0150Z...
At 2300Z, at KLAX, the marine layer depth was 800 feet. The top
of the inversion was at 2700 feet with a temperature of 30 degrees
Celsius.
Low confidence exact timing and flight category of low cigs at
coastal TAF sites due to scattered marine deck interaction with
mid level clouds currently moving off the coast of SW CA. The
timing of low cigs may be off by +/- 3 hours a break in low cigs
are possible for KLAX KLGB and KOXR between 04Z and 10Z. There is
a 40 percent chance of lifr cigs/vsbys at KLAX and KLGB between
06Z and 15Z. There is a 20 percent chance that vfr conditions
prevail at KSMX and KSBP. There is a 20 percent chance of brief
IFR cigs between 11Z and 16Z at KBUR and KVNY.
KLAX...Low confidence in 06Z TAFs due to uncertainty in timing and
category of low cigs. The timing of low cigs may be off by +/- 3
hours a break in low clouds possible between 04Z and 10Z. There
is a 40 percent chance of lifr cigs/vsbys mainly between 06Z and
15Z. There is a 30 percent chance that IFR cigs return by 29/00Z.
There is also a 10 percent chance that ifr to low MVFR cigs
prevail throughout the day.
KBUR...Good confidence in the 00Z TAF. There is a 20 percent
chance of brief IFR cigs between 11Z and 16Z.
&&
.MARINE...28/200 PM...
For the Outer Waters, good confidence in current forecast. Gusty
northwest winds will continue through the week. The strongest
winds will occur across PZZ670/673 with a high likelihood of
SCA level winds continuing for most of the week. For PZZ676,
there will be a chance of SCA level winds from Wednesday through
the rest of the week.
For the Inner Waters, good confidence in current forecast. There
is a high likelihood of conditions remaining below SCA levels
through the week.
Patchy dense fog in the coastal waters will be possible in the
overnight and morning hours through the week, particularly south
of Point Conception.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect until 3 AM PDT Wednesday For
zones 670-673. (See LAXMWWLOX).
&&
$$
PUBLIC...MW
AVIATION...Munroe
MARINE...Sweet
SYNOPSIS...Seto
weather.gov/losangeles
[top]
Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
511 PM PDT TUE JUN 28 2016
.UPDATE...UPDATED AIR QUALITY ISSUES.
&&
.SYNOPSIS...
Temperatures will rise to much above normal today. Upper level
disturbance will trigger showers and possible thunderstorms today
across the Kern County Desert and mountain area. Showers and
thunderstorms are possible through thursday in the Sierra.
&&
.DISCUSSION...The monsoonal high parked over the four corners
region over the last couple days has continued to bring above
normal temperatures to most of the area. A weak disturbance has
rounded the high and has brought a surge of moisture into eastern
Kern County and northward along the crest. There has been some
cloud cover in place for most of the day over this area as well
thanks to this moisture. This should keep temperatures down a few
degrees.
The moisture has also brought some sprinkles and/or virga to Kern
County this morning...with a couple locations reporting a trace of
precipitation. The showery activity has edged north into the
Sierra Nevada this afternoon. Not expecting much precipitation
with these showers either, though with thunderstorm potential in
place into the evening across both the Sierra Crest and Kern
Mountains a few locations could see some measurable precip.
Tomorrow looks like another hot day across most of the forecast
area. There will be some lingering moisture across the eastern
edge of the forecast area which would bring another round of
showers and thunderstorms in the evening.
Then Thursday the upper high will weaken enough and slide eastward
allowing for a slight cooling trend. This cooling will be enhanced
by a shortwave trough edging onshore. In fact, could see near or
slightly above normal temperatures by the weekend or a cooling of
5 or so degrees.
Other than some lingering showers and thunderstorms along the
Sierra Crest until Friday and Kern County Mountains and Desert
over the 36 hours the forecast looks dry.
&&
.AVIATION...
Smoke from the Erskine wildfire will produce reduced visibilities in
the vicinity of Lake Isabella. Local mountain obscurations in
showers and thunderstorms over the southern Sierra Nevada and
Tehachapi mountains. Otherwise, VFR conditions will prevail
throughout the Central CA interior during the next 24 hours.
&&
.AIR QUALITY ISSUES...
On Wednesday June 29 2016... Unhealthy in Fresno and Kern Counties
and Sequoia National Park and Forest. Unhealthy for sensitive
groups in Kings... Madera... Merced and Tulare Counties.
Further information is available at Valleyair.org
&&
.CERTAINTY...
The level of certainty for days 1 and 2 is medium.
The level of certainty for days 3 through 7 is medium.
Certainty levels include low...medium...and high. Please visit
www.weather.gov/hnx/certainty.php for additional information
an/or to provide feedback.
&&
.HNX Watches/Warnings/Advisories...
NONE.
&&
$$
weather.gov/hanford
Area Forecast Discussion
National Weather Service San Francisco Bay Area
504 PM PDT TUE JUN 28 2016
.SYNOPSIS...High pressure over the region will result in
continued very warm and dry inland conditions through midweek.
Some cooling is anticipated late in the week and more so into the
weekend, especially over inland areas. Dry weather and near
seasonal temperatures are likely for the Forth of July Holiday
Weekend.
&&
.DISCUSSION...as of 2:45 PM PDT Tuesday...Current observed
temperatures are ranging wildly this afternoon with 97F at
Livermore and 59F at Monterey. Several unofficial sensors are
also reporting temperatures at or above 100F throughout the inland
valleys to the north, east, and south of the Bay Area. This large
temperature gradient is the result of a broad 595DM ridge over the
Four Corners region warming from the east and cool marine air
cooling from the west, with a thermal trough in between. As of
2PM, temperatures are 2 to 6 degrees cooler than this time
yesterday with slightly more cooling seen further inland than near
the coast.
Visible satellite shows a thinly veiled marine layer across much
of coastal California this afternoon. Portions of this layer will
mix out into the afternoon before the layer deepens slightly late this
evening before pushing inland overnight. Patchy dense fog and
drizzle will again be possible for coastal areas tomorrow morning,
as well as all of the remaining mornings of this week.
The Four Corners ridge is modeled to gradually become flat and
weakened over the central CONUS through the remainder of the
week. Temperatures will cool aloft as a result and lead to a
cooling trend at the surface with temperatures bottoming out on
Saturday. Temperatures will shift from the above average to
below average from today to Saturday by a few to several degrees
with the largest difference seen further inland.
Locally, the models show a relatively quiet pattern through the
next several days. A weak mean trough with an unimpressive
embedded disturbance will form over California/Oregon late in the
week into early next week as high pressure rebuilds over the
central CONUS. This will likely lead to moderated near normal
values and fair weather for Sunday and beyond.
&&
.AVIATION...as of 4:59 PM PDT Tuesday...Mainly clear skies prevail
this afternoon with the exception of areas of coastal stratus
along the coast. The marine layer remains shallow at around 1000
feet. The marine layer is anticipated to deepen slightly overnight
as a weak trough moves over the region resulting in more stratus
coverage over area terminals tonight. Moderate onshore flow will
persist through this evening then gradually weaken overnight.
Vicinity of KSFO...VFR conditions are expected to prevail through
09Z tonight at which point cigs bkn008 are expected to begin
impact the terminal. First guess at morning burnoff is 1730Z
Wednesday morning. West winds around 20 kt with afternoon gusts to
around 25 kt expected through this evening. Moderate confidence.
SFO Bridge Approach...Similar to KSFO.
Monterey Bay Terminals...VFR conditions are expected to prevail
this evening with cigs returning around 3330Z at KMRY and 0700Z
at KSNS. Moderate west winds around 10 to 15 kt expected through
this evening...winds will ease overnight becoming light and
locally variable. Moderate confidence.
&&
.MARINE...as of 2:45 PM PDT Tuesday...A strong surface pressure
gradient will maintain gusty northwesterly winds across a majority
of the coastal waters through at least Thursday. These winds will
support large, steep seas through late week. A long period
southerly swell will also move into the waters midweek. The
surface pressure gradient is anticipated to weaken Thursday
evening bringing lighter winds to the inner coastal waters for the
weekend.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.Tngt...SCA...Pt Reyes to Pigeon Pt 0-10 nm
SCA...Pigeon Pt to Pt Pinos 0-10 nm
SCA...Pt Arena to Pt Reyes 0-10 nm
SCA...Pt Arena to Pigeon Pt 10-60 nm
SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm
SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm
SCA...SF Bay until 8 PM
&&
$$
PUBLIC FORECAST: DRP
AVIATION: CW
MARINE: Larry
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[top]
Area Forecast Discussion
National Weather Service Eureka CA
333 PM PDT TUE JUN 28 2016
.SYNOPSIS...An upper level ridge will continue to bring hot and
dry conditions to interior areas of Northwest California through
Wednesday. A cooling trend will begin on Thursday as a trough
settles over the Pacific Northwest. Seasonable temperatures and
mostly cloudy conditions will persist along much of the coast for
at least the next few days.
&&
.DISCUSSION...The ridge axis has only shifted slightly east to
near the eastern Yukon border in the last 24 hours which has
resulted in very little sensible weather change as compared to
yesterday. However, a shortwave ridge in the wake of the
shortwave trough passage yesterday has allowed thickness values to
increase today and high temperatures this afternoon should be a
couple degrees warmer than yesterday. An approaching longwave
trough will push the ridge farther east on Wednesday. High
temperatures will likely still reach 100 degrees Wednesday
afternoon in some interior valley locations, but a cooling trend
will be in store as the trough moves into the Pacific Northwest
and heights fall. Temperatures will fall back to near or slightly
above normal and the marine layer will deepen along the coast
Friday into this weekend. It is possible that enough mixing may
occur along the coast to dissipate much of the coastal cloudiness
each afternoon late in the week and this weekend depending on the
exact positioning of the upper trough. Additionally, if enough
moisture can be brought into the region, the cooler air aloft will
have the potential to support convective development over the
interior mountains. Considering the pattern is not particularly
supportive of thunderstorms, only very low chances for
precipitation have been included in the forecast on Thursday when
a mid-level cap is predicted to be weakest. /RPA
&&
.AVIATION...Marine clouds continued to blanket the North Coast
today even extending into local coastal valleys, a typical June
pattern. Inland areas were basically clear today (except for a few
brief pockets of fog in river valley this morning). Therefore
interior areas will remain basically clear through the forecast
period. Back along the coast, limited and brief clearing mid-late
afternoon and early evening expected along sections near the
immediate coast. However, marine clouds will once again redevelop
and push farther into coastal and near coastal inland areas this
evening through Wednesday morning. Breezy winds expected at
airfield along the coast and a few coastal valleys through
afternoon-early/evening. Several offshore eddies caused CEC and
ACV winds to vary from mostly south-west in the afternoon.
&&
.MARINE...Northerly winds and short period seas will continue to
increase tonight through Wednesday as high pressure offshore
interacts with a thermal trough over the California interior.
For tonight, GALE WARNINGS for wind gusts to 35KT remain in effect
for the outer waters 10-60nm offshore. Northerly wind waves of 10 ft
or more will build tonight as well. GALE force wind gusts along with
very steep wind waves are expected to continue Wed morning before
northerly winds approach FULL GALE Wednesday afternoon and evening.
Strong northerly winds and very steep wind waves will continue Wed
night and Thu. Persistent northerly breezes and steep seas will most
likely continue on Fri and Sat across the outer waters.
Closer to shore and inside 10nm, primary concern Wed through Fri
will be the short period wind waves. Short period wind waves should
steadily increase tonight and Wed. SMALL CRAFT ADVISORies for steep
and hazardous wind waves remain in effect tonight through Wed. If
the northerly winds offshore reach full gale, then seas inside 10nm
north of Cape Mendocino will become very steep at 10 ft or more late
Wednesday afternoon and evening. Therefore, a HAZARDOUS SEAS WATCH
remains in effect through Wed night. Wave conditions may ease up
some Thu morning, before wave heights increase to 10 ft or more
again Thu afternoon and evening again. Steep and hazardous seas will
probably continue on Fri and Sat, especially north of the Cape.
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
Small Craft Advisory until 5 PM PDT Wednesday FOR PZZ450.
Hazardous Seas Watch from Wednesday afternoon through late
Thursday night FOR PZZ450.
Gale Warning until 11 PM PDT Friday FOR PZZ470.
Small Craft Advisory until 9 PM PDT Saturday FOR PZZ455.
Gale Warning until 9 PM PDT Saturday FOR PZZ475.
&&
$$
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http://www.weather.gov/eureka/zonemap.png
[top]
Area Forecast Discussion
National Weather Service Sacramento CA
315 PM PDT TUE JUN 28 2016
.SYNOPSIS...
Hot and mainly dry weather this week. Isolated late day
thunderstorms possible over the mountains.
&&
.DISCUSSION...
24 hr temp trends at 20z were running close to yesterday...albeit
there was less of a N/NWly zephyr at the surface than yesterday. Max
temps still expected to trend similar to yesterday...although the
Carquinez Strait and portions of the west Delta may be a degree or
two cooler. Still can`t rule out the potential for a record tying
max temp for DTS this afternoon...given the late "run-for-glory"
with a SW wind and minimal marine layer as air from the hot
pavement of US-50 wafts over the DTS sensor late in the day. The
table below shows the records for the rest of the month and
illustrates that only DTS has a chance/potential for a record
tying max temp today.
June 28th June 29th June 30th
RDD 108 (2013) 108 (2013) 113 (2015)
City 111 (1918) 111 (1974) 112 (1950)
RBL 112 (1977) 114 (1950) 113 (2015)
DTS 108 (2009) 107 (2013) 112 (1934)
SAC 108 (2009) 107 (2013) 109 (1950)
MYV 111 (2009) 109 (2013) 111 (1934)
SCK 110 (2009) 106 (2013) 110 (1972)
MOD 111 (2009) 109 (2009) 108 (1950)
An upper trof approaching the Pac NW coast will nudge the Wrn
portion of the 4-Corners High Ewd on Wed with a weak "baggy" trof
establishing itself over the region Thu/Fri. The short-wave along
the SErn CA/Srn NV border will work its way Nwd tonight and Wed
bringing some monsoonal moisture with it and the chance of
T-storms mainly S of Tahoe. Some of the moisture may result in
some patchy cloudiness over the Nrn SJV zone...and Srn portions of
the Motherlode/Sierra Nevada zones later tonite and Wed...however
most of the T-storm activity should be E of the Sierra Crest. Late
Wed...Thu...Fri the aforementioned upper trof is expected to
weaken the ridge enough Norcal to initiate minor cooling. The
small chance of T-storms over portions of the mtns will continue
on Thu although moisture will be lacking as the monsoonal moisture
will be shunted Ewd by the upper trof. Some moisture could remain
along the Sierra Crest for some afternoon CU/TCU on Fri. JHM
&&
.EXTENDED DISCUSSION (Saturday THROUGH Tuesday)
Upper troughing regime will persist along the Pacific Northwest during
this forecast period. This pattern should result in near-normal temperatures
across interior northern California this weekend into early next
week. Dry conditions are expected, with daytime highs in the 90s
across the Valley, and 70s-80s over higher elevations.
&&
.AVIATION...
VFR conditions next 24 hour period across TAF sites. Light winds
generally less than 10 knots, except for occasional gusts near
the Delta region.
&&
.STO Watches/Warnings/Advisories...
None.
&&
$$
Area Forecast Discussion
National Weather Service Sacramento CA
315 PM PDT TUE JUN 28 2016
.SYNOPSIS...
Hot and mainly dry weather this week. Isolated late day
thunderstorms possible over the mountains.
&&
.DISCUSSION...
24 hr temp trends at 20z were running close to yesterday...albeit
there was less of a N/NWly zephyr at the surface than yesterday. Max
temps still expected to trend similar to yesterday...although the
Carquinez Strait and portions of the west Delta may be a degree or
two cooler. Still can`t rule out the potential for a record tying
max temp for DTS this afternoon...given the late "run-for-glory"
with a SW wind and minimal marine layer as air from the hot
pavement of US-50 wafts over the DTS sensor late in the day. The
table below shows the records for the rest of the month and
illustrates that only DTS has a chance/potential for a record
tying max temp today.
June 28th June 29th June 30th
RDD 108 (2013) 108 (2013) 113 (2015)
City 111 (1918) 111 (1974) 112 (1950)
RBL 112 (1977) 114 (1950) 113 (2015)
DTS 108 (2009) 107 (2013) 112 (1934)
SAC 108 (2009) 107 (2013) 109 (1950)
MYV 111 (2009) 109 (2013) 111 (1934)
SCK 110 (2009) 106 (2013) 110 (1972)
MOD 111 (2009) 109 (2009) 108 (1950)
An upper trof approaching the Pac NW coast will nudge the Wrn
portion of the 4-Corners High Ewd on Wed with a weak "baggy" trof
establishing itself over the region Thu/Fri. The short-wave along
the SErn CA/Srn NV border will work its way Nwd tonight and Wed
bringing some monsoonal moisture with it and the chance of
T-storms mainly S of Tahoe. Some of the moisture may result in
some patchy cloudiness over the Nrn SJV zone...and Srn portions of
the Motherlode/Sierra Nevada zones later tonite and Wed...however
most of the T-storm activity should be E of the Sierra Crest. Late
Wed...Thu...Fri the aforementioned upper trof is expected to
weaken the ridge enough Norcal to initiate minor cooling. The
small chance of T-storms over portions of the mtns will continue
on Thu although moisture will be lacking as the monsoonal moisture
will be shunted Ewd by the upper trof. Some moisture could remain
along the Sierra Crest for some afternoon CU/TCU on Fri. JHM
&&
.EXTENDED DISCUSSION (Saturday THROUGH Tuesday)
Upper troughing regime will persist along the Pacific Northwest during
this forecast period. This pattern should result in near-normal temperatures
across interior northern California this weekend into early next
week. Dry conditions are expected, with daytime highs in the 90s
across the Valley, and 70s-80s over higher elevations.
&&
.AVIATION...
VFR conditions next 24 hour period across TAF sites. Light winds
generally less than 10 knots, except for occasional gusts near
the Delta region.
&&
.STO Watches/Warnings/Advisories...
None.
&&
$$
Area Forecast Discussion
National Weather Service Phoenix AZ
305 PM MST TUE JUN 28 2016
.UPDATE...
Updated Aviation and Fire Weather sections.
&&
.SYNOPSIS...
High pressure will move somewhat north and east of Arizona this week
allowing warm temperatures to prevail, but also bring a couple of
weather disturbances through the state. An increase in monsoon
moisture will accompany these weather systems, providing a threat of
afternoon and evening showers and thunderstorms the remainder of
week.
&&
.DISCUSSION...
Tonight through Saturday...
Model guidance and water vapor imagery showed the slow moving
inverted trof coming out of the Gulf of CA into an area near the
Mexican border south of Tucson this afternoon. At the same time,
high speed visible satellite imagery showed a mid level disturbance
moving toward southeast AZ from southern New Mexico. As a result 2
pm radar and satellite imagery showed a growing area of
thunderstorms from Tucson southward. At the same time there were
developing thunderstorms over the higher terrain of central AZ north
of Phoenix. Meso-scale models forecast gusty outflow winds to move
toward Phoenix late today sparking mtn convection east of Phoenix,
followed by a stronger outflow boundary from the Tucson area late
this evening. As a result, convective outflows and or colliding
boundaries could generate a threat of showers and thunderstorms
around the greater Phoenix area tonight, similar to last night when
Sky Harbor Airport recorded 0.01 inches of rain with heavier amounts
around the city. Our southeast CA and southwest AZ zones will be dry
for the most part tonight.
Another and perhaps stronger upper level disturbance is forecast to
move from just off the central Baja west coast tonight, into
southern AZ late Wednesday afternoon. Interesting is the MOS precip
guidance is forecasting a higher probability of precipitation over
the south central AZ, including Phoenix Wednesday evening.
More recognizable upper level disturbances, like those currently
seen on water vapor imagery 650 miles southwest of San Diego, are
forecast to move into southern AZ Thu and Fri. Timing of these
disturbances are uncertain, and with the monsoon moisture in place,
a broad brush chance approach to afternoon and evening thunderstorms
is perhaps the best approach for now. The threat of tstms will be
primarily confined to portions of southwest and south central AZ for
the tonight through Saturday period.
Sunday through Tuesday...
Models are forecasting a somewhat airmass to overspread our forecast
area, southeast CA to south central AZ, from the west this period.
Although drier air pushes into southeast CA and the Colorado River
Valley, south central and southeast AZ will still hang on to some
remnant moisture. The monsoon moisture boundary retreats east
into the far southeast corner of AZ Mon and Tue.
However perhaps more importantly Monday through Wednesday is a major
adjustment in the upper level flow pattern. Winds at and above 300
mb become broadly anti-cyclonic, devoid of disturbances, and
certainly imply a very stable subsident airmass that could kill the
threat of afternoon/evening high elevation mountain storms.
Therefore this period will be a quiet one, meaning mostly clear
skies, warmer afternoon temperatures, with just a very slight chance
of an afternoon mountain thunderstorms in southern Gila County
bordering the White Mountains.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
Thunderstorms developing north through southeast of metro Phoenix
will likely increase in coverage (especially over Gila County)
through 00Z. Outflow from distant storms will likely affect at least
some portion of metro Phoenix this evening - most likely after 02Z.
Confidence in storms directly hitting any given TAF site not high
enough yet to include TEMPO or prevailing TSRA. However, TAFs
reflect the scenario of nearby storms causing erratic winds this
evening. There are some indications that lingering shower/storm
activity could go til 09Z. But by that point, likely this would only
be debris clouds (bases AOA FL100) with otherwise light winds.
Anticipate debris clouds lingering well past sunrise. Anticipate
southeasterly surface winds to last for much of the day with
westerly struggling to develop in the afternoon.
Southeast California/Southwest Arizona including KIPL and KBLH:
A stray thunderstorm is quite possible (mainly over La Paz County)
through 06Z otherwise anticipate debris clouds (bases AOA FL100)
with isolated weak showers after 03Z (mainly near and east of Lower
Colorado River Valley). Surface winds will favor south and
southeasterly directions (being stronger Wednesday than today).
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Thursday through Tuesday...
Enhanced humidities and storm chances will continue into Saturday.
Humidities will trend down substantially Sunday and Monday. In fact,
minimum humidities on the low deserts will be near 10 percent by
Monday. Similarly, overnight recovery will trend down to only fair.
Thunderstorm chances will be confined to the higher terrain of south-
central AZ Sun-Tue and be only slight. Apart from strong erratic
winds associated with thunderstorms, southerly breeziness can be
expected over southwest AZ and southeast CA Thu-Sat(less so over
south-central AZ). Winds will favor southwesterly directions next
week.
&&
.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...AJ
FIRE WEATHER...AJ
Area Forecast Discussion
National Weather Service San Francisco Bay Area
246 PM PDT TUE JUN 28 2016
.SYNOPSIS...High pressure over the region will result in
continued very warm and dry inland conditions through midweek.
Some cooling is anticipated late in the week and more so into the
weekend, especially over inland areas. Dry weather and near
seasonal temperatures are likely for the Forth of July Holiday
Weekend.
&&
.DISCUSSION...as of 2:45 PM PDT Tuesday...Current observed
temperatures are ranging wildly this afternoon with 97F at
Livermore and 59F at Monterey. Several unofficial sensors are
also reporting temperatures at or above 100F throughout the inland
vallies to the north, east, and south of the Bay Area. This large
temperature gradient is the result of a broad 595DM ridge over the
Four Corners region warming from the east and cool marine air
cooling from the west, with a thermal trough in between. As of
2PM, temperatures are 2 to 6 degrees cooler than this time
yesterday with slightly more cooling seen further inland than near
the coast.
Visible satellite shows a thinly veiled marine layer across much
of coastal California this afternoon. Portions of this layer will
mix out into the afternoon before the layer deepens slightly late this
evening before pushing inland overnight. Patchy dense fog and
drizzle will again be possible for coastal areas tomorrow morning,
as well as all of the remaining mornings of this week.
The Four Corners ridge is modeled to gradually become flat and
weakened over the central CONUS through the remainder of the
week. Temperatures will cool aloft as a result and lead to a
cooling trend at the surface with temperatures bottoming out on
Saturday. Temperatures will shift from the above average to
below average from today to Saturday by a few to several degrees
with the largest difference seen further inland.
Locally, the models show a relatively quiet pattern through the
next several days. A weak mean trough with an unimpressive
embedded disturbance will form over California/Oregon late in the
week into early next week as high pressure rebuilds over the
central CONUS. This will likely lead to moderated near normal
values and fair weather for Sunday and beyond.
&&
.AVIATION...as of 11:10 AM PDT Tuesday...Mostly clear skies are
being reported at the terminals this morning. The current visible
satellite image is also showing mostly clear skies over land with
stratus just off shore. According to the Fort Ord profiler and san
Francisco Exploratorium`s radiometer the marine layer is right
around 1200 feet deep. With gentle onshore flow expect the marine
layer to deepen and impact the terminals overnight.
Vicinity of KSFO...VFR conditions are expected to prevail through
0900Z at which point cigs bkn008 are expected to begin impact the
terminal. First guess at morning burnoff is 1730Z Wednesday
morning. West winds are expected to reach 24 kt this afternoon
with gusts to 32 kt possible.
Confidence is moderate.
SFO Bridge Approach...Similar to KSFO.
Monterey Bay Terminals...VFR conditions are expected to prevail
today with cigs returning around 3330Z at KMRY and 0700Z at KSNS.
Westerly winds are expected to reach 8 kt at KMRY and 14 kt at
KSNS.
Confidence is moderate.
&&
.MARINE...as of 02:15 PM PDT Tuesday...A strong surface pressure
gradient will maintain gusty northwesterly winds across a majority
of the coastal waters into the weekend. these winds will also
result in large, steep seas through late week. a long period
southerly swell will also move into the waters through midweek.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.Tngt...SCA...Pt Reyes to Pigeon Pt 0-10 nm
SCA...Pigeon Pt to Pt Pinos 0-10 nm
SCA...Pt Arena to Pt Reyes 0-10 nm
SCA...Pt Arena to Pigeon Pt 10-60 nm
SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm
SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm
SCA...SF Bay until 8 PM
&&
$$
PUBLIC FORECAST: DRP
AVIATION: Larry
MARINE: Larry
Visit us at www.weather.gov/sanfrancisco
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www.Facebook.com/nwsbayarea
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Area Forecast Discussion
National Weather Service San Francisco Bay Area
246 PM PDT TUE JUN 28 2016
.SYNOPSIS...High pressure over the region will result in
continued very warm and dry inland conditions through midweek.
Some cooling is anticipated late in the week and more so into the
weekend, especially over inland areas. Dry weather and near
seasonal temperatures are likely for the Forth of July Holiday
Weekend.
&&
.DISCUSSION...as of 2:45 PM PDT Tuesday...Current observed
temperatures are ranging wildly this afternoon with 97F at
Livermore and 59F at Monterey. Several unofficial sensors are
also reporting temperatures at or above 100F throughout the inland
vallies to the north, east, and south of the Bay Area. This large
temperature gradient is the result of a broad 595DM ridge over the
Four Corners region warming from the east and cool marine air
cooling from the west, with a thermal trough in between. As of
2PM, temperatures are 2 to 6 degrees cooler than this time
yesterday with slightly more cooling seen further inland than near
the coast.
Visible satellite shows a thinly veiled marine layer across much
of coastal California this afternoon. Portions of this layer will
mix out into the afternoon before the layer deepens slightly late this
evening before pushing inland overnight. Patchy dense fog and
drizzle will again be possible for coastal areas tomorrow morning,
as well as all of the remaining mornings of this week.
The Four Corners ridge is modeled to gradually become flat and
weakened over the central CONUS through the remainder of the
week. Temperatures will cool aloft as a result and lead to a
cooling trend at the surface with temperatures bottoming out on
Saturday. Temperatures will shift from the above average to
below average from today to Saturday by a few to several degrees
with the largest difference seen further inland.
Locally, the models show a relatively quiet pattern through the
next several days. A weak mean trough with an unimpressive
embedded disturbance will form over California/Oregon late in the
week into early next week as high pressure rebuilds over the
central CONUS. This will likely lead to moderated near normal
values and fair weather for Sunday and beyond.
&&
.AVIATION...as of 11:10 AM PDT Tuesday...Mostly clear skies are
being reported at the terminals this morning. The current visible
satellite image is also showing mostly clear skies over land with
stratus just off shore. According to the Fort Ord profiler and san
Francisco Exploratorium`s radiometer the marine layer is right
around 1200 feet deep. With gentle onshore flow expect the marine
layer to deepen and impact the terminals overnight.
Vicinity of KSFO...VFR conditions are expected to prevail through
0900Z at which point cigs bkn008 are expected to begin impact the
terminal. First guess at morning burnoff is 1730Z Wednesday
morning. West winds are expected to reach 24 kt this afternoon
with gusts to 32 kt possible.
Confidence is moderate.
SFO Bridge Approach...Similar to KSFO.
Monterey Bay Terminals...VFR conditions are expected to prevail
today with cigs returning around 3330Z at KMRY and 0700Z at KSNS.
Westerly winds are expected to reach 8 kt at KMRY and 14 kt at
KSNS.
Confidence is moderate.
&&
.MARINE...as of 02:15 PM PDT Tuesday...A strong surface pressure
gradient will maintain gusty northwesterly winds across a majority
of the coastal waters into the weekend. these winds will also
result in large, steep seas through late week. a long period
southerly swell will also move into the waters through midweek.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.Tngt...SCA...Pt Reyes to Pigeon Pt 0-10 nm
SCA...Pigeon Pt to Pt Pinos 0-10 nm
SCA...Pt Arena to Pt Reyes 0-10 nm
SCA...Pt Arena to Pigeon Pt 10-60 nm
SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm
SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm
SCA...SF Bay until 8 PM
&&
$$
PUBLIC FORECAST: DRP
AVIATION: Larry
MARINE: Larry
Visit us at www.weather.gov/sanfrancisco
Follow us on Facebook and twitter at:
www.Facebook.com/nwsbayarea
www.twitter.com/nwsbayarea
Area Forecast Discussion
National Weather Service Phoenix AZ
226 PM MST TUE JUN 28 2016
.SYNOPSIS...
High pressure will move somewhat north and east of Arizona this week
allowing warm temperatures to prevail, but also bring a couple of
weather disturbances through the state. An increase in monsoon
moisture will accompany these weather systems, providing a threat of
afternoon and evening showers and thunderstorms the remainder of
week.
&&
.DISCUSSION...
Tonight through Saturday...
Model guidance and water vapor imagery showed the slow moving
inverted trof coming out of the Gulf of CA into an area near the
Mexican border south of Tucson this afternoon. At the same time,
high speed visible satellite imagery showed a mid level disturbance
moving toward southeast AZ from southern New Mexico. As a result 2
pm radar and satellite imagery showed a growing area of
thunderstorms from Tucson southward. At the same time there were
developing thunderstorms over the higher terrain of central AZ north
of Phoenix. Meso-scale models forecast gusty outflow winds to move
toward Phoenix late today sparking mtn convection east of Phoenix,
followed by a stronger outflow boundary from the Tucson area late
this evening. As a result, convective outflows and or colliding
boundaries could generate a threat of showers and thunderstorms
around the greater Phoenix area tonight, similar to last night when
Sky Harbor Airport recorded 0.01 inches of rain with heavier amounts
around the city. Our southeast CA and southwest AZ zones will be dry
for the most part tonight.
Another and perhaps stronger upper level disturbance is forecast to
move from just off the central Baja west coast tonight, into
southern AZ late Wednesday afternoon. Interesting is the MOS precip
guidance is forecasting a higher probability of precipitation over
the south central AZ, including Phoenix Wednesday evening.
More recognizable upper level disturbances, like those currently
seen on water vapor imagery 650 miles southwest of San Diego, are
forecast to move into southern AZ Thu and Fri. Timing of these
disturbances are uncertain, and with the monsoon moisture in place,
a broad brush chance approach to afternoon and evening thunderstorms
is perhaps the best approach for now. The threat of tstms will be
primarily confined to portions of southwest and south central AZ for
the tonight through Saturday period.
Sunday through Tuesday...
Models are forecasting a somewhat airmass to overspread our forecast
area, southeast CA to south central AZ, from the west this period.
Although drier air pushes into southeast CA and the Colorado River
Valley, south central and southeast AZ will still hang on to some
remnant moisture. The monsoon moisture boundary retreats east
into the far southeast corner of AZ Mon and Tue.
However perhaps more importantly Monday through Wednesday is a major
adjustment in the upper level flow pattern. Winds at and above 300
mb become broadly anti-cyclonic, devoid of disturbances, and
certainly imply a very stable subsident airmass that could kill the
threat of afternoon/evening high elevation mountain storms.
Therefore this period will be a quiet one, meaning mostly clear
skies, warmer afternoon temperatures, with just a very slight chance
of an afternoon mountain thunderstorms in southern Gila County
bordering the White Mountains.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL: For the
morning into the afternoon, expect winds to favor the southeast at
the terminals, mostly below 12kt with a slight tendency to then turn
towards the west. Variable mid/high level cloud decks will move
across the greater Phoenix area with most bases aoa 12k feet and
most broken decks aoa 15k feet. May see a few light showers or virga
from these decks this morning. Once again expect mountain
thunderstorms to develop east of Phoenix later this afternoon and
evening, a few of which may move into the central deserts and affect
the terminals after 03z or so. Will not get overly aggressive in the
TAFs this early and will stick with VCTS for now. Have added in
earlier than usual switch to east/southeast winds at the TAF sites,
mostly after 04z based on expected outflow winds moving into the
lower deserts.
Southeast California/Southwest Arizona including KIPL and KBLH: Most
convective weather to stay east of the area today and into the
evening hours with skies to be mostly sunny. Most cloud decks to be
few to sct with bases above 12k feet. Winds will be rather light
next 24 hours and occasionally variable but favoring the southeast
to south, likely turning back towards the west this evening at KIPL.
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Thursday through Monday... Temperatures will continue to cool as
moisture increases, with south central Arizona lowering below 105
degrees and even below 100 after Thursday and into the weekend.
Modest warming expected later in the period as air mass dries a bit.
Monsoon moisture levels continue to increase over the region with
chances for afternoon thunderstorms expected across south central
Arizona through Friday and slight chances further west towards the
lower Colorado River valley. Over the weekend and into early next
week a drying trend from the west is expected and by Sunday isolated
thunderstorms should be mostly confined to higher terrain areas to
the east of Phoenix. Any storms that develop have the ability to
produce lightning, gusty winds, and wetting rains, especially
storms that develop across south central Arizona through Friday.
Minimum humidities through Friday will be highly elevated,
especially west of the lower Colorado River valley, with readings
generally 20 to 30 percent, and even higher across southern Gila
County. Readings will fall between 15 and 20 percent Saturday, then
down mostly below 15 percent Sunday into Monday as drier air spreads
over the area from the southwest. Winds each day will be on the
light side for the most part, mostly below 15 mph, but will be
locally breezy at times from the south west of Maricopa county and
along the lower Colorado River valley mainly during the afternoon
hours each day.
&&
.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...CB
FIRE WEATHER...Deemer/CB
[top]
Area Forecast Discussion
National Weather Service Reno NV
213 PM PDT TUE JUN 28 2016
.SYNOPSIS...
Highs around 100 degrees are expected for lower elevations of
western Nevada through Friday as high pressure remains over the
Great Basin. A few thunderstorms are possible south of Highway 50
each afternoon through Friday. There could be a few thunderstorms
just north of Highway 50 along the eastern Sierra Friday
afternoon, but this is highly uncertain for now. For the holiday
weekend, dry conditions are expected with temperatures remaining
above average.
&&
.SHORT TERM...
The primary changes to the forecast today involve trying to
better refine the areas where convection may develop through
Thursday.
The GFS...NAM and HRRR all have development starting closer to
the Sierra crest in Mono County this afternoon...then move this
development farther north and east into southern Lyon and Mineral
counties by this evening. There is a bit less movement to the east
for Wednesday afternoon and evening but we also see stronger late
afternoon and early evening westerly flow that would aid in
developing convection north along the Pine Nut Mountains and
possibly as far north as the southern Virginia Range.
Overall...the instability is not overwhelming either day...but
the very hot temperatures and a weak short wave in the mid levels
is providing just enough lift to aid the development of storms.
Dry sub-cloud layers today should begin to moisten just a bit by
Wednesday. Dry storms today should give way to hybrid storms by
Wednesday and slow storm motions will also help produce some brief
moderate to heavy downpours in the strongest storms. Gusty outflow
winds of up to 50 mph along with dry lightning strikes outside of
the rain cores are also possible.
Storms redevelop Thursday...but this development could be just a
bit farther east initially. Slow storm motions should again help
produce rain in the strongest storms...even with dry air near the
surface. By Friday the model guidance begins to diverge as the GFS
is a bit more progressive with southwest flow aloft shearing most
of the moisture to the east while the NAM is digging a trough
toward California that is producing backing flow in the mid
levels. That allows more moisture to be drawn north and initiates
convection along the Sierra and into northeast California. While
the ECMWF has a little development in far northern California it
mostly supports the GFS. So for now we will leave the higher pops
out of the forecast for Friday.
Well above normal high temperatures continue into Friday with a
few records possible Wednesday and Thursday. Highs reach the
98-103 range in the lower valleys with upper 80s to lower 90s in
the Sierra valleys.
.LONG TERM...Saturday through Tuesday...
Only minimal changes were made to the extended forecast. The GFS
is still trying to maintain or rebuild the ridge through Tuesday
while the latest ECMWF shows more of an elongated trough along
the CA coast. The ECMWF would provide slightly cooler temperatures
but the chance for stronger winds. The GFS solution supports
higher temperatures and the possibility of weak convection in the
favored convergence zones...especially Mono County...each day.
The GEFS ensemble members show a variety of solutions with no
operational model favored over any other. Thus...we will maintain
a dry forecast with slightly above average temperatures through
the extended period. Bear in mind this forecast remains highly
uncertain and confidence is moderate at best that the current
forecast will play out as stated.
&&
.AVIATION...
Thunderstorms are possible each afternoon and evening south of
Highway 50 from near the Sierra crest east to about Highway 95
through Friday. There is an outside chance storms could develop
farther north along the eastern side of the Sierra late Friday
afternoon...but there is great uncertainty in this solution for
now.
Typical zephyr winds are likely each day through Friday with gusts
in the 20-25 knot range immediately east of the Sierra. Lighter
gusts are expected east of Highway 95 except in the vicinity of
thunderstorms. VFR conditions are also likely each day through
Friday except in the vicinity of thunderstorms. XX
&&
.REV Watches/Warnings/Advisories...
NV...None.
CA...None.
&&
$$
For more information from the National Weather Service visit...
http://weather.gov/reno
AREA FORECAST DISCUSSION
National Weather Service San Diego CA
138 PM PDT MON JUN 27 2016
.SYNOPSIS...
High pressure aloft will continue hot weather for inland areas
through Wednesday followed by slow cooling into next weekend as
high pressure aloft weakens and a weak trough of low pressure
develops over the Pacific Northwest. Mid and high level moisture
associated with a disturbance moving through the region will
bring a slight chance of afternoon and early evening thunderstorms
with gusty winds through Wednesday, mainly near the mountains.
The marine layer and onshore flow will keep coastal high
temperatures cooler with areas of night and morning low clouds and
fog.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
Visible and radar imagery continues to show mid and high level
clouds and some light radar returns associated with an easterly
wave which is moving through the region. Most of the fast moving
light radar returns are resulting in virga or sprinkles. However,
a band of stationary showers has developed and persisted on the
desert slopes near Lake Arrowhead over the past hour. The 12Z
Miramar sounding shows precipitable water having increased to 1.48
inches, although the majority of the moisture appears to be above
700 mb, with a dry layer noted below 700 mb until you reach the 10
deg C marine layer inversion near 1000 ft MSL. It is due to the
dry layer below 700 mb that most of the precipitation may
evaporate before reaching the ground, which is why most of it will
appear as virga or maybe some sprinkles. The amount of cloud
cover we have today, and which locations receive more sunlight
than others, is playing a factor in how hot we get today. Due to
the mid and high clouds, temperatures have been slightly reduced
at 1 pm today compared to 1 pm yesterday in the Inland Empire, all
mountain areas, the High Deserts and Coachella Valley. However,
with some higher surface dewpoints in the area (low 60s shown
currently over most coast, valley and desert areas), it will feel
more muggy and uncomfortable.
Despite the increase in moisture and the wave moving overhead, the
elevated instability parameters shown by the forecast models for
this afternoon and evening are still not impressive. Also, the
strong easterly flow is not conducive for thunderstorms that
develop over the mountains to maintain their structure. Thus, the
latest HRRR run shows some light shower activity but not much in
the way of thunderstorm activity this afternoon. Nevertheless,
slight chance for thunderstorms remains in the forecast today for
the mountains, with some activity possibly being blown west into
the valleys.
Meanwhile, marine layer stratus along the coast this morning was
able to clear pretty quickly, but has since re-developed along the
immediate coast, likely due to the decently strong marine layer
inversion.
Models show drier air intruding into Southern California Tuesday
and Wednesday as flow turns southerly in the wake of the easterly
wave, resulting in less of a chance for afternoon and early
evening mountain thunderstorms on those days. However, the
clearer skies and strong ridge over the four corners region should
result in hotter conditions, with highs 5-10 degrees above normal.
Continued hot for inland areas on Wednesday, with 850 mb
temperatures in the deserts reaching 27-29 deg C, and near 26-27
deg C in the valleys. A Heat Advisory continues for the deserts,
mountains and valleys through Wednesday. Despite the ridge
weakening on Thursday, looks like the 850 mb temperatures do not
decrease too much, so hot conditions may continue.
Cooler Friday into the weekend as a trough moves into the Pacific
Northwest, with a deepening of the marine layer as well, resulting
in night and morning stratus into the coast and portions of the
valleys.
&&
.AVIATION...
271950Z...Coast/Valleys...Areas of sct-bkn clouds based 800-1200
feet MSL with tops around 1500 ft MSL over the coastal waters
otherwise mostly clear. After 28/0z this evening low clouds bkn-
ovc based 800-1200 feet MSL with tops around 1500 ft MSL will push
inland about 15 miles with local visibilities 2-4 miles along higher
coastal terrain/mesas. There is a moderate risk that the coastal low
clouds will again be patchy so the confidence is low on the timing
and duration of the bkn low clouds at KSAN tonight. Some low clouds
may temporarily move in on the sea breeze but will leave out of the
KSAN TAF.
Isolated SHRA/TSRA near the mountains through 28/00z this afternoon
with CB bases near 9000 ft MSL and tops to near 35000 ft MSL.
Mountains and Deserts...Sct-bkn clouds based around 9000 feet MSL
with unrestricted visibilities. This afternoon through 28/00Z
isolated SHRA/TSRA with cloud bases 9000 ft MSL and tops to
35000 ft MSL will be possible over the mountains.
&&
.MARINE...
100 pm...No hazardous marine weather is expected through Friday.
&&
.BEACHES...
100 pm...The long period south swell will continue to decrease, but
3-5 foot surf will continue on the southwest facing beaches through
tonight. The surf will lower to 2 to 4 feet Tuesday. Another long-
period south swell from 200 degrees will bring 4-7 foot surf to
southwest facing beaches late Wednesday and Thursday along with
dangerous rip currents.
&&
.FIRE WEATHER...
Slight chance of dry lightning over the mountains and portions of
the valleys this afternoon and evening, as an easterly wave moves
through the region. Drying will start to take place Tuesday, with
maybe just enough moisture leftover on Tuesday and Wednesday to
produce isolated afternoon thunderstorms over the mountains.
&&
.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
&&
.SGX Watches/Warnings/Advisories...
CA...Heat Advisory until 8 PM PDT Wednesday for Apple and Lucerne
Valleys-Coachella Valley-Riverside County Mountains-San
Bernardino County Mountains-San Bernardino and Riverside
County Valleys-The Inland Empire-San Diego County Deserts-
San Diego County Mountains-San Gorgonio Pass Near Banning.
PZ...None.
&&
$$
PUBLIC/FIRE WEATHER...Harrison
AVIATION/MARINE...Small
AREA FORECAST DISCUSSION
National Weather Service San Diego CA
852 AM PDT MON JUN 27 2016
.SYNOPSIS...
High pressure aloft will continue hot weather for inland areas
through Wednesday followed by slow cooling into next weekend as
high pressure aloft weakens and a weak trough of low pressure
develops over the Pacific Northwest. Mid and high level moisture
associated with a disturbance moving through the region will
bring a slight chance of afternoon and early evening thunderstorms
with gusty winds through Wednesday, mainly near the mountains.
The marine layer and onshore flow will keep coastal high
temperatures cooler with areas of night and morning low clouds and
fog.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
Visible and radar imagery is showing an easterly upper level wave
moving through the region, bringing mid and high level clouds and
some light radar returns which are likely producing only virga or
sprinkles. The 12Z Miramar sounding shows precipitable water
having increased to 1.48 inches, although the majority of the
moisture appears to be above 700 mb, with a dry layer noted below
700 mb until you reach the 10 deg C marine layer inversion near
1000 ft MSL. It is due to the dry layer below 700 mb that most of
the precipitation may evaporate before reaching the ground, which
is why most of it will appear as virga or maybe some sprinkles.
These clouds will continue to move through Southern California
through the day, although the moisture field from the NAM12 shows
clearing skies intruding in from the south in the afternoon. The
amount of cloud cover we have today, and which locations receive
more sunlight than others, will play a factor in not only how hot
we get today, but also the amount of day-time heating induced
instability. Due to the mid and high clouds, temperatures may be
reduced slightly compared to yesterday. However, with some higher
surface dewpoints in the area (low 60s shown currently over most
coast, valley and desert areas), it may feel more muggy and
uncomfortable.
Despite the increase in moisture and the wave moving overhead, the
elevated instability parameters shown by the forecast models for
this afternoon are not impressive. Also, the strong easterly flow
is not conducive for thunderstorms that develop over the mountains
to maintain their structure. Thus, the latest HRRR run doesn`t
show much shower or thunderstorm activity this afternoon.
Nevertheless, a slight chance for thunderstorms remains in the
forecast today for the mountains, with some activity possibly
being blown west into the valleys.
Meanwhile, marine layer stratus was able to develop over coastal
areas today. Stratus should be able to clear out of inland areas by
late morning, although the decently strong inversion could keep
some low clouds hanging around at the coast.
Models show drier air intruding into Southern California Tuesday
as flow turns southerly in the wake of the easterly wave,
resulting in less of a chance for afternoon mountain
thunderstorms. However, the clearer skies and strong ridge over
the four corners region should result in hotter conditions, with
highs 5-10 degrees above normal. Continued hot for inland areas on
Wednesday, with 850 mb temperatures in the deserts reaching 27-29
deg C, and near 26-27 deg C in the valleys. A Heat Advisory
continues for the deserts, mountains and valleys through
Wednesday. Despite the ridge weakening on Thursday, looks like
the 850 mb temperatures do not decrease much, if at all, so hot
conditions may continue.
Cooler Friday into the weekend as a trough moves into the Pacific
Northwest, with a deepening of the marine layer as well, resulting
in night and morning stratus into the coast and portions of the
valleys.
&&
.AVIATION...
271530Z...Coast/Valleys...Areas of sct-bkn clouds based 800-1200
feet MSL with tops around 1800 ft MSL will burn back to out over the
coastal waters. Local vis 2-4 miles along higher coastal
terrain/mesas. After 28/06z this evening low clouds bkn-ovc based
800-1200 feet MSL with tops around 1800 ft MSL will push inland
about 15 miles with local visibilities 2-4 miles along higher
coastal terrain/mesas. There is a moderate risk that the coastal low
clouds will again be patchy so the confidence is low on the timing
and duration of the bkn low clouds at KSAN tonight.
Mountains and Deserts...Sct-bkn clouds based around 10000 feet MSL
with unrestricted visibilities. This afternoon between 27/19Z and
28/00Z isolated SHRA/TSRA with cloud bases 9000 ft MSL and tops to
35000 ft MSL will be possible over the mountains.
&&
.MARINE...
830 am...No hazardous marine weather is expected through Friday.
&&
.BEACHES...
830 am...The long period south swell will continue to decrease, but
3-5 foot surf will continue on the southwest facing beaches today.
The surf will lower to 2 to 4 feet Tuesday. Another long-period
south swell from 200 degrees will bring 4-7 foot surf to southwest
facing beaches late Wednesday and Thursday along with dangerous rip
currents.
&&
.FIRE WEATHER...
Slight chance of dry lightning over the mountains and portions of
the valleys this afternoon and evening, as an easterly wave moves
through the region. Drying will take place Tuesday through
Wednesday, with maybe just enough moisture leftover on Tuesday to
produce isolated afternoon thunderstorms over the mountains.
&&
.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
&&
.SGX Watches/Warnings/Advisories...
CA...Heat Advisory until 8 PM PDT Wednesday for Apple and Lucerne
Valleys-Coachella Valley-Riverside County Mountains-San
Bernardino County Mountains-San Bernardino and Riverside
County Valleys-The Inland Empire-San Diego County Deserts-
San Diego County Mountains-San Gorgonio Pass Near Banning.
PZ...None.
&&
$$
PUBLIC/FIRE WEATHER...Harrison
AVIATION/MARINE/BEACHES...Small
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
612 PM CDT TUE JUN 28 2016
...Update to aviation forecast discussion...
.SHORT TERM...(This Evening through Wednesday)
Issued at 320 PM CDT TUE JUN 28 2016
19Z water vapor shows a broad upper ridge over the four corners
region and an upper trough moving east of the great lakes region.
This sets up northwest flow from the northern Rockies through the
central plains. At the surface, weak ridging stretches from the
upper Midwest into northeast KS, but there is not a strong gradient
in temps or dewpoints denoting a synoptic frontal boundary. Surface
obs suggest the better low level convergence is over eastern CO with
the easterly upslope winds. Think the festering convection over
south central KS is a result of a weak MCV from the morning
convection.
The forecast for tonight and Wednesday is focused on convection
currently ongoing over eastern WY. The NAM and GFS indicate a
convectively induced vort max for this evening`s convection over the
high plains should propagate across the forecast area by Wednesday
morning. However the ECMWF and GEM are much less obvious with any
MCV. Additionally the high resolution models that do a better job of
simulating convection seem to be mixed on coverage of possible
storms overnight. The overall expectation is for the convection over
WY to move towards northern KS late tonight. Models indicate that
mid level lapse rates should still be steep enough for some elevated
instability mainly across central KS. The low level jet is also
progged to gradually veer to the southwest by 12Z which could air in
an MCS holding together. Based on storms from this morning, think
there could be a damaging wind risk if a decent cold pool forms with
the MCS. Because of the uncertainty in storm coverage, the forecast
has POPs increasing to 50 percent by the early morning hours
Wednesday. But it appears the north central KS counties stand the
better chance for precip as the instability axis and nose of the low
level jet appear to be set up across central KS. If indeed an MCS
forms, showers and storms could persist over part of the forecast
area through the morning and into the early afternoon. Again the
main uncertainty is where the possible MCS will track so POPs
through the day Wednesday have been held in the chance category.
Lows tonight are forecast to be in the mid 60s. Highs Wednesday are
expected to be in the lower and middle 80s due to the weak surface
ridging and possible cloud cover.
.LONG TERM...(Wednesday Night through Tuesday)
Issued at 320 PM CDT TUE JUN 28 2016
Moderate precipitation chances continue to inhabit these periods.
Northwest flow aloft continues into the end of the week. Isentropic
lift is depicted on GFS and NAM on the 305 to 310K surfaces
Wednesday night and may produce convection into Thursday, mainly in
southern areas. This is where the greater lift is progged, as lower
level winds increase ahead of a cold front pushing south into the
area. Front looks to hold up not far to the south for continued
thunderstorm chances Thursday night into Friday night as flow
becomes more zonal aloft for continued isentropic lift setup. Upper
wave is fairly well agreed upon to move east across the region
Saturday night into Sunday. Still appears a general drying trend
into the early week with ridging increasing aloft.
Convergence along the Thursday front looks weak, and with
some convection potentially lingering into the day, questions
on instability remain, but at least a small risk for pulse severe
weather exists. Next best chance for severe weather looks to be
Saturday and Saturday night with potential for the boundary to
lift back in. Perhaps the bigger impacts could come from heavy
rain with several periods of rain potential, good moisture in
place, and front nearly parallel to upper flow.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
Issued at 610 PM CDT TUE JUN 28 2016
There is a chance for showers and storms tomorrow morning through
the afternoon. There could brief periods of moderate rainfall that
cause MVFR conditions. Overall confidence in the exact location
and timing is low at this point.
&&
.TOP Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Wolters
LONG TERM...65
AVIATION...Sanders
Area Forecast Discussion
National Weather Service Dodge City KS
600 PM CDT TUE JUN 28 2016
...Updated Aviation...
.SHORT TERM...(This evening through Wednesday)
Issued at 305 PM CDT Tue Jun 28 2016
For this evening, an outflow boundary will continue push south of
Dodge City, with some strong to severe storms possible. Hail to
quarter size and heavy rainfall possible. A supercell or two is also
possible with larger hail with some stronger upper winds today than
yesterday.
Then later tonight a Mesoscale Convective Complex (MCS)
is forecast to move in from Nebraska. Will carry highest chances
across south central sections then blend smaller chances west.
Severe storms are not expected later tonight, except for some strong
winds to 50 mph and small hail, lots of lightning and areas of heavy
rainfall. Overnight lows will be in the mid to upper 60s.
For Wednesday, upper level northwest flow will continue with a cold
front near the Oklahoma border. Will carry 20 to 30 percent chances
wtih the better chances south and east of Dodge City. South winds
shift to the east and northeast with a cold front. Highs look to be
from the upper 80s near and east of Dodge City with mid 90s for
parts of southwest Kansas.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 323 PM CDT Tue Jun 28 2016
For the period of Wednesday Night into next Tuesday, an active
northwest flow pattern continues into Thursday then begins to
flatten out with more shortwaves into Sunday. By Monday and into
Tuesday chances for rainfall become less as any jet stream features
shift north. Areas of thunderstorms are forecast daily with the best
chances mainly in the evenings and overnights into Sunday.
Highs will be cooler, with mainly lower to mid 80s into Sunday, then
warming to around 90 to 95 on Monday and Tuesday. Overnight lows
will be in the mid to upper 60s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 600 PM CDT Tue Jun 28 2016
Thunderstorms have ended temporarily across SW KS, but outflow
boundaries left over from previous storms will make winds variable
and erratic at the terminals early this evening. VFR will prevail
early tonight along with SE surface winds. A large thunderstorm
complex entering NW Nebraska at 23z will race SE overnight, with
model consensus suggesting it will begin to affect the terminals
during the 06-07z Wed timeframe. Primary impact from this complex
will be gusty outflow winds to near 50 kts. HRRR solution suggests
a weakening squall line will extend from near HYS to near GCK
during this timeframe, and used this as a first approximation for
TEMPO groups for convective wind gusts. Highest confidence on
impacts to aviation through Wednesday morning is at HYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 67 91 67 88 / 30 20 30 40
GCK 66 93 67 87 / 20 20 20 40
EHA 66 95 66 89 / 10 20 30 50
LBL 67 94 67 90 / 20 30 30 50
HYS 66 87 65 84 / 50 40 40 40
P28 68 90 69 90 / 30 30 40 50
&&
.DDC Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Kruse
LONG TERM...Kruse
AVIATION...Turner
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
309 PM CDT MON JUN 27 2016
.SHORT TERM...(This Evening through Tuesday)
Issued at 309 PM CDT MON JUN 27 2016
A broad upper level trough was located across the upper Great
Lakes and will amplify as it digs southeast across lower MI. The
upper flow will become more northwesterly and a short-wave trough
across eastern WY and will translate southeast across western NE
into central KS by the mid morning hours of Tuesday.
A weak front extend from central IA, southwest into south central
NE, then recurved northwest into the NE PNHDL. There may be enough
surface convergence ahead of the surface front across southeast NE
for isolated to scattered thunderstorms to develop late this
afternoon or early evening. The HRRR model seems to have a handle on
the thunderstorms developing across southwest IA, and shows
thunderstorms developing southwest ahead of the weak surface
boundary, and then moving southeast across much of northeast KS. If
thunderstorms manage to develop across southern NE, they will then
move southeast into the northern counties of the CWA. MLCAPE will be
around 3,000 J/kg and the 0-6 KM effective shear will be 30 KTS.
Therefore, any isolated thunderstorms late this afternoon and early
evening across the northern counties of the CWA may be strong to
severe with the primary hazard being large hail and damaging wind
gusts. If thunderstorms do develop along the weak front late this
afternoon and early evening they should weaken and dissipate through
the mid evening hours.
Tonight, The mesoscale models are showing two thunderstorm complexes
developing across the high plains of eastern CO and western NE. Most
numerical models show these thunderstorm complexes moving south-
southeast across western and central KS, remaining just west of the
CWA. However, the NMM and GFS show the northern thunderstorm complex
that develops across the western NE panhandle, moving southeast
across northwest KS into the western counties of the CWA between 12Z
and 15Z TUE. If an MCS manages to develop it may be able to maintain
itself due the sufficient MUCAPE and vertical windshear. An MCS may
bring the threat for damaging wind gusts to north central KS near
sunrise through the mid morning hours of Tuesday.
Tuesday, after the potential for morning thunderstorms across north
central KS, skies will become partly cloudy. It looks dry for the
remainder of the day. Upslope flow across the higher terrain of
northeast CO, eastern WY and the western NE panhandle will cause
scattered thunderstorms to develop and these storms will organize
into an MCS late Tuesday afternoon across the central high plains.
Highs Tuesday afternoon will reach the mid to upper 80s.
.LONG TERM...(Tuesday Night through Monday)
Issued at 309 PM CDT MON JUN 27 2016
In general, chances for precip remain in the forecast through the
extended period as models continue to show a conditionally
unstable airmass with possible pertibations within the flow.
Although confidence in storms occurring at any give time are below
normal as the forecast should be driven primarily by mesoscale
features, and thunderstorms in one period could affect the next
couple periods.
For Tuesday night through Thursday, the better chances for
thunderstorms looks to be Wednesday or Wednesday night as there
continues to be signs for a vort max to move through northwest
flow aloft. However there are timing differences with vort max as
well as with the location of a possible convective system among
the various solutions. Because of this, POPs where kept in the 30
to 50 percent range. Models continue to support temps a little
closer to or below normal temps with highs in the lower and mid
80s and lows in the mid 60s.
For Thursday night through the weekend, the ECMWF and GFS are
showing a little better defined cold front moving into the area
and stalling out across east central or southern KS as the
synoptic pattern becomes a little less amplified and flow aloft
becomes a little more westerly. Since there is not a big change in
airmass with the front pushing through well south of the forecast
area, potential instability remains possible with disturbances
coming off the Rockies. Therefore it is difficult to rule out
precip chances through this period as well. The reenforcement of
surface ridging should keep highs in the lower and mid 80s and
lows in the mid 60s through the weekend.
By next Monday, there are indications for shortwave ridging to
develop over the central plains and the thermal ridge to build
back in from the southwest. With no obvious forcing seen in the
models, have trended POPs into the slight chance and temps should
be warming up again with some lower 90s possible.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday Afternoon)
Issued at 1238 PM CDT MON JUN 27 2016
Scattered CU will develop at the terminals with bases of 4,000 to
6,000 feet. There may be an thunderstorm around the terminals late
this afternoon or this evening. High clouds from a thunderstorm
complex moving southeast across central KS will probably prevent
ground fog from forming by sunrise. However, if skies remain clear
there could be some patchy dense ground fog around the terminals near
sunrise Tuesday morning.
&&
.TOP Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Gargan
LONG TERM...Wolters
AVIATION...Gargan
Area Forecast Discussion
National Weather Service Flagstaff AZ
246 AM MST WED JUN 29 2016
.SYNOPSIS... Monsoon activity will be on the increase over the
next few days as a moist southerly flow develops across Arizona.
Look for showers and thunderstorms each day with the best
potential for heavy rain arriving on Thursday and Friday.
&&
.DISCUSSION...High pressure centered over the four corners region
will gradually drift to a position over Texas during the next few
days.
For today...ample moisture is situated across northern Arizona.
As daytime heating progresses and instability builds another round
of thunderstorms is expected across northern Arizona. Storms will
be most numerous along and south of a line extending from the
Grand Canyon southeastward through Flagstaff and Show Low. Heavy
rain will be possible with stronger storms with 1 to 2 inch
downpours possible. As always gusty winds, small hail and cloud-
to-ground lightning with storms. Pretty typical monsoon stuff.
For Thursday through Saturday...Southerly flow will deliver deep
monsoon moisture with widespread showers and thunderstorms. The
deepest moisture will be located from the Mogollon Rim southward
where storms will be the most numerous. At this time the best
combination of flow, instability and moisture will be on Thursday
and Friday roughly along and west of a Payson-Flagstaff-Grand
Canyon line. Looks like the highest potential for heavy rain
producing storms so far this monsoon. Stay tuned as details
emerge.
From Sunday onward...A drier and stabilizing westerly flow
develops. Most areas across northern Arizona will see only a
slight chance of showers and storms. The only exception will be
the mountain areas along the Arizona/New Mexico border where
lingering moisture will result in scattered storms.
&&
.AVIATION...For the 12Z Package...Isolated -SHRA possible this
morning. Scattered to numerous TSRA expected to develop aft 17Z with
the focus of activity over the higher terrain of northern AZ.
Locally heavy rain, small hail, and gusty winds possible with
storms. Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...An active monsoon weather pattern will continue
through the week with scattered to numerous showers and
thunderstorms each day. An increase in moisture will raise the
threat for heavy rain by Thursday. Gusty outflow winds also possible
near any showers or storms.
Friday through Sunday...Active monsoon weather continues through
Saturday with close to average temperatures. A downturn in
thunderstorm activity is possible by Sunday or early next week.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...McCollum
AVIATION...MCS
For Northern Arizona weather information visit
weather.gov/flagstaff
[top]
Area Forecast Discussion
National Weather Service Tucson AZ
915 PM MST TUE JUN 28 2016
.SYNOPSIS...Scattered showers and thunderstorms through Friday. A
drying trend will then limit thunderstorms to mainly near the New
Mexico border by early next week.
&&
.DISCUSSION...Late afternoon activity was a little frisky in spots
with localized heavy rainers, mostly across eastern Pima county. Ran
a quick update earlier this evening to switch focus for the remainder
of tonight to account for storms overnight. Regional radar at 9 pm
showed scattered showers and isolated thunderstorms across eastern
Pinal county east across Graham and Greenlee counties. The HRRR
runs this evening have been rather consistent with the scenario of
overnight storms pushing to the southwest. Areas that didn`t see any
storms earlier today, especially parts of eastern Pima county, still
have some elevated CAPE to be utilized. With PW values in the 1.20"
to 1.60" range across the area, locally heavy rainers are more of a
concern overnight versus severe.
South of the border across Sonora Mexico, satellite imagery showed
a large complex of thunderstorms with clouds tops as cold as -82C.
For comparison the thunderstorms near Tucson this afternoon had cloud
tops as cold at -60C. Thunderstorm outflows to move into the Gulf of
California which will likely initiate a gulf surge overnight thus
bringing an increase of lower level moisture for Wednesday and
Thursday.
With the potential for this influx of low-level moisture to increase
across the lower deserts of southern Arizona, we are looking at an
uptick in stronger thunderstorms on Wednesday, especially across
Pinal, Pima and Santa Cruz counties.
&&
.AVIATION...VALID THRU 30/06Z.
Scattered showers and thunderstorms will push southwest during the
overnight hours. Of the terminal sites, KTUS and KOLS have the best
chance to see thunderstorms overnight. MVFR conditions possible near
some heavy rainers, otherwise VFR conditions with plenty of
debris clouds around. Debris clouds to diminish after sunrise
Wednesday morning with scattered thunderstorms once again developing
near the higher terrain Wednesday afternoon. Wind speeds generally
less than 12 kts except 30-35 kts in and around stronger
thunderstorms. Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...With plenty of moisture and instability around there
will be daily rounds of scattered showers and thunderstorms through
Friday. The strongest storms will be capable of very strong winds and
heavy downpours especially during the mid afternoon to early evening
hours. Moisture will diminish across the region Saturday onward
resulting in a decrease in the amount of convection each day. By
Monday any isolated convection will be limited to the mountains near
the eastern border and over the White Mountains.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Area Forecast Discussion
National Weather Service Flagstaff AZ
909 PM MST TUE JUN 28 2016
.SYNOPSIS...
Monsoon activity will be on the increase over the next few days
as a moist southerly flow develops across Arizona. Look for
showers and thunderstorms each day with the best potential for
heavy rain arriving on Thursday and Friday.
&&
.DISCUSSION...
Isolated showers and thunderstorms will continue this evening and
overnight across northern Arizona, with most activity looking to
be across the White Mountains for at least the next couple hours.
Storms are anticipated to become more numerous again by late
Wednesday morning and afternoon.
&&
.PREV DISCUSSION /425 PM MST/...
For Wednesday through Friday...The high center gradually shifts
to a position over Texas with a southerly flow developing across
Arizona. Model forecasts continue to indicate that this moist
southerly wind flow will draw deeper moisture into the region from
over Northwest Mexico and the Gulf of California. At this point,
it looks like Thursday and Friday show the best potential for
storms producing very heavy rainfall.
From Saturday onward...The flow becomes more westerly with origins
from over the eastern Pacific Ocean. Under this regime look for a
bit of drying and stabilization with a downturn in thunderstorm
activity anticipated.
&&
.AVIATION...
For the 06Z Package...A few showers and thunderstorms may
continue this evening and overnight, mainly south of a KPAN- KSJN
line. More numerous showers and thunderstorms are expected to
redevelop after 17Z Wednesday. Aviation discussion not updated for
TAF amendments.
&&
.FIRE WEATHER...
An active monsoon pattern is now in place across the district.
This means daily shower and thunderstorm activity. Storm motion
become nearly stationary and terrain driven by Wednesday and
Thursday. Expect erratic and gusty winds near showers and storms.
Friday through Sunday...Expect active monsoon weather with
scattered showers and thunderstorms each day. Activity may
decrease somewhat by Sunday as drier westerly flow develops, but
this remains to be seen. Temperatures will be right around
seasonal averages.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...KD/RR
AVIATION...KD
FIRE WEATHER...Peterson
For Northern Arizona weather information visit
weather.gov/flagstaff
[top]
Area Forecast Discussion
National Weather Service Phoenix AZ
805 PM MST TUE JUN 28 2016
.SYNOPSIS...
High pressure will move somewhat north and east of Arizona this week
allowing warm temperatures to prevail, but also bring a couple of
weather disturbances through the state. An increase in monsoon
moisture will accompany these weather systems, providing a threat of
afternoon and evening showers and thunderstorms the remainder of
week.
&&
.DISCUSSION...
Evening objective analysis depicted several low amplitude waves
captured within easterly flow through the SW Conus with the most
notable vorticity center through eastern New Mexico. 00Z KTWC
sounding sampled a nice looking 10 g/kg mixing ratio through the
boundary layer with little inhibition while KPSR showed 8 g/kg with
more capping around the H7 layer. Despite the MLcape near 500 J/kg
in a weakly capped environment allowing scattered deep convection
surround the forecast area, distinct subsidence more downstream from
ascent structures have caused much of storms over SE AZ and northern
AZ to fizzle.
However, more organized storms have materialized through eastern AZ
and activity continues to percolate through Gila county. Numerous
weak outflow boundaries were converging through the lower elevations
of central AZ likely modifying the environment. In addition,
easterly steering flow through the H7-H5 layer should also advect a
lobe of better midlevel moisture towards the forecast area. Thus,
feel activity will continue later into the evening and overnight
hours associated with shortwave activity. Have made some minor
adjustment to pops based on this analysis.
&&
.PREVIOUS DISCUSSION...
/305 PM MST TUE JUN 28 2016/
Tonight through Saturday...
Another and perhaps stronger upper level disturbance is forecast to
move from just off the central Baja west coast tonight, into
southern AZ late Wednesday afternoon. Interesting is the MOS precip
guidance is forecasting a higher probability of precipitation over
the south central AZ, including Phoenix Wednesday evening.
More recognizable upper level disturbances, like those currently
seen on water vapor imagery 650 miles southwest of San Diego, are
forecast to move into southern AZ Thu and Fri. Timing of these
disturbances are uncertain, and with the monsoon moisture in place,
a broad brush chance approach to afternoon and evening thunderstorms
is perhaps the best approach for now. The threat of tstms will be
primarily confined to portions of southwest and south central AZ for
the tonight through Saturday period.
Sunday through Tuesday...
Models are forecasting a somewhat airmass to overspread our forecast
area, southeast CA to south central AZ, from the west this period.
Although drier air pushes into southeast CA and the Colorado River
Valley, south central and southeast AZ will still hang on to some
remnant moisture. The monsoon moisture boundary retreats east
into the far southeast corner of AZ Mon and Tue.
However perhaps more importantly Monday through Wednesday is a major
adjustment in the upper level flow pattern. Winds at and above 300
mb become broadly anti-cyclonic, devoid of disturbances, and
certainly imply a very stable subsident airmass that could kill the
threat of afternoon/evening high elevation mountain storms.
Therefore this period will be a quiet one, meaning mostly clear
skies, warmer afternoon temperatures, with just a very slight chance
of an afternoon mountain thunderstorms in southern Gila County
bordering the White Mountains.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
Converging outflow boundaries and lift from waves approaching from
the east should allow thunderstorms to develop east of terminal
sites, and move towards/through the metro during the late evening
hours. Somewhat lower confidence in coverage of actual storms near
terminal sites, but shifting outflow winds from an E/NE direction
seem more likely. Periods of variable directions are also probable
after storms/outflow pass until a predominant east flow develops
tonight. Cigs will remain in a 10K ft range with/around these
storms.
Probability and coverage of storms appears even better late
Wednesday afternoon and evening with more direct impact likely for
terminals. Morning and early afternoon hours should remain quiet
with higher cloud decks, light easterly winds, and minimal to no
aviation impacts.
Southeast California/Southwest Arizona including KIPL and KBLH:
Little aviation impacts through Wednesday afternoon with storms
remaining well east of SE CA. While surface winds will favor a south
and southeasterly direction, outflow boundaries from distant storms
may cause abrupt wind shifts, or variable winds overnight.
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Thursday through Tuesday...
Enhanced humidities and storm chances will continue into Saturday.
Humidities will trend down substantially Sunday and Monday. In fact,
minimum humidities on the low deserts will be near 10 percent by
Monday. Similarly, overnight recovery will trend down to only fair.
Thunderstorm chances will be confined to the higher terrain of south-
central AZ Sun-Tue and be only slight. Apart from strong erratic
winds associated with thunderstorms, southerly breeziness can be
expected over southwest AZ and southeast CA Thu-Sat(less so over
south-central AZ). Winds will favor southwesterly directions next
week.
&&
.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...MO/Vasquez
AVIATION...MO
FIRE WEATHER...AJ
Area Forecast Discussion
National Weather Service Tucson AZ
718 PM MST TUE JUN 28 2016
.SYNOPSIS...Scattered showers and thunderstorms will occur through
tonight, with the favored areas south of Tucson and across the White
Mountains. Increasing moisture and a favorable flow regime will then
provide even greater coverage of showers and thunderstorms Wednesday
through Friday. A drying trend will then limit thunderstorms to
mainly near the New Mexico border by early next week.
&&
.UPDATE...Ran a quick update to the forecast based on latest runs of
the HRRR which has been rather consistent on a rim shot to move
across the area during the overnight hours. Will continue to
monitor.
&&
.DISCUSSION...Visible satellite imagery and KEMX WSR-88D showed
isolated to scattered convection this afternoon, mainly south and
west of I-10. So far the storms seem to be relatively tame, since
they are being sheared apart by low level easterly flow and upper
level southwesterly flow. It`s still feeling soupy out there with
sfc dewpoints holding steady in the 50s. 28/18z CIRA LPW indicated
the bulk of moisture was located near the international border and
across the western half of Pima County. Not as much activity as
anticipated over the White Mountains, but the latest runs of the
HRRR/WRFEMS are hinting at convection developing over that area
later on this evening, so there`s still time. Overall, it still
looks like scattered showers and thunderstorms will continue into
this evening, with isolated activity into the overnight hours.
The 28/12Z runs of the GFS/ECMWF remain in very good agreement
through at least the first part of the holiday weekend. The
anticipation is for an upswing in convective activity starting
tomorrow, with a focus on Thursday into Friday especially. High
pressure aloft currently located near the preferred Four Corners
region will remain quasi-stationary through tomorrow, with a shift
toward the east and southeast through the end of the work week. In
response, expect upper level flow to becoming increasingly
southeasterly and then southerly, which will really aid in ramping
up our moisture in the form of a Gulf surge. As such, wouldn`t be
surprised to see sfc dewpoints jump into the mid to upper 60s as
early as Wednesday night into Thursday morning. In addition, the
GFS/NAM indicate PWAT will jump to between 1.6 and 2 inches by
00Z Friday, with the highest values across western Pima County.
Thereafter, PWAT values look to drop to around 1.25 inches by 12z
Saturday, and continue to decrease into early next week as we lose
our monsoonal flow and a weak upper ridge/westerly flow develops
over the southwestern deserts. This will shut us down for a few days
with regard to convection, with the exception being areas adjacent
to the NM border and across the mountains. The GFS then tries to
reconsolidate high pressure over the four corners while the ECMWF
maintains westerly flow. As such, have continued with just slight
chance PoPs for eastern zones at the end of the forecast period. We
will also have to keep an eye on the tropics, as both the GFS/ECMWF
bring a system southwest of the Baja tip late next week. Something
to watch.
Expect a slow decrease in daytime temperatures through Friday, when
highs will top out 5-10 degrees below normal. We will then warm
right back up to normal levels by Sunday into early next week.
&&
.AVIATION...VALID THRU 30/00Z.
Scattered showers and thunderstorms will be in and around the
terminals through 29/08Z. KTUS, KDUG, and KOLS have the best chance
of seeing activity. VFR conditions will be the rule, however, brief
MVFR conditions in heavy rainfall are possible. Additionally, wind
gusts upwards of 30 kts will be possible in and around the strongest
storms. Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...With plenty of moisture and instability we
will have daily rounds of scattered showers and thunderstorms
through Friday. The strongest storms will be capable of very strong
winds and heavy downpours especially during the mid afternoon to
early evening hours. Moisture will diminish across the region
Saturday onward resulting in a decrease in the amount of convection
each day. By Monday any isolated convection will be limited to the
mountains near the eastern border and over the White Mountains.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
1134 PM CDT TUE JUN 28 2016
...Update to aviation forecast discussion...
.SHORT TERM...(This Evening through Wednesday)
Issued at 320 PM CDT TUE JUN 28 2016
19Z water vapor shows a broad upper ridge over the four corners
region and an upper trough moving east of the great lakes region.
This sets up northwest flow from the northern Rockies through the
central plains. At the surface, weak ridging stretches from the
upper Midwest into northeast KS, but there is not a strong gradient
in temps or dewpoints denoting a synoptic frontal boundary. Surface
obs suggest the better low level convergence is over eastern CO with
the easterly upslope winds. Think the festering convection over
south central KS is a result of a weak MCV from the morning
convection.
The forecast for tonight and Wednesday is focused on convection
currently ongoing over eastern WY. The NAM and GFS indicate a
convectively induced vort max for this evening`s convection over the
high plains should propagate across the forecast area by Wednesday
morning. However the ECMWF and GEM are much less obvious with any
MCV. Additionally the high resolution models that do a better job of
simulating convection seem to be mixed on coverage of possible
storms overnight. The overall expectation is for the convection over
WY to move towards northern KS late tonight. Models indicate that
mid level lapse rates should still be steep enough for some elevated
instability mainly across central KS. The low level jet is also
progged to gradually veer to the southwest by 12Z which could air in
an MCS holding together. Based on storms from this morning, think
there could be a damaging wind risk if a decent cold pool forms with
the MCS. Because of the uncertainty in storm coverage, the forecast
has POPs increasing to 50 percent by the early morning hours
Wednesday. But it appears the north central KS counties stand the
better chance for precip as the instability axis and nose of the low
level jet appear to be set up across central KS. If indeed an MCS
forms, showers and storms could persist over part of the forecast
area through the morning and into the early afternoon. Again the
main uncertainty is where the possible MCS will track so POPs
through the day Wednesday have been held in the chance category.
Lows tonight are forecast to be in the mid 60s. Highs Wednesday are
expected to be in the lower and middle 80s due to the weak surface
ridging and possible cloud cover.
.LONG TERM...(Wednesday Night through Tuesday)
Issued at 320 PM CDT TUE JUN 28 2016
Moderate precipitation chances continue to inhabit these periods.
Northwest flow aloft continues into the end of the week. Isentropic
lift is depicted on GFS and NAM on the 305 to 310K surfaces
Wednesday night and may produce convection into Thursday, mainly in
southern areas. This is where the greater lift is progged, as lower
level winds increase ahead of a cold front pushing south into the
area. Front looks to hold up not far to the south for continued
thunderstorm chances Thursday night into Friday night as flow
becomes more zonal aloft for continued isentropic lift setup. Upper
wave is fairly well agreed upon to move east across the region
Saturday night into Sunday. Still appears a general drying trend
into the early week with ridging increasing aloft.
Convergence along the Thursday front looks weak, and with
some convection potentially lingering into the day, questions
on instability remain, but at least a small risk for pulse severe
weather exists. Next best chance for severe weather looks to be
Saturday and Saturday night with potential for the boundary to
lift back in. Perhaps the bigger impacts could come from heavy
rain with several periods of rain potential, good moisture in
place, and front nearly parallel to upper flow.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday Night)
Issued at 1130 PM CDT TUE JUN 28 2016
There is a complex of storms in central NE that is moving
southeastward. There is a chance they hold together and make it to
the taf sites. Isolated showers and storms out ahead of this line
are also possible. A few models are developing another round
tomorrow afternoon although confidence is low at this point.
&&
.TOP Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Wolters
LONG TERM...65
AVIATION...Sanders
Area Forecast Discussion
National Weather Service Dodge City KS
808 PM CDT TUE JUN 28 2016
.UPDATE...
Issued at 808 PM CDT Tue Jun 28 2016
Increased thunderstorm coverage tonight across mainly the northern
and western zones. Per SPC coordination and MCD, a severe
thunderstorm watch will likely be issued soon for the northern
zones. Damaging winds are likely from this expected squall line.
HRRR suggests a track almost due south along the instability axis
along the CO/KS border. with the storms reaching the Elkhart
vicinity around 3 AM. Included severe/damaging wind wording in the
grids starting at 1 AM for mainly the northern zones.
UPDATE Issued at 623 PM CDT Tue Jun 28 2016
All thunderstorms have ended this evening, and have removed all
pops from the grids for the next several hours. Earlier
thunderstorm complex has exited into Oklahoma. Various outflow
boundaries are seen on radar, but further initiation is unlikely
through 10 pm. An impressive complex of storms is entering NW
Nebraska currently, producing wind gusts of 60-80 mph. Latest HRRR
solution suggests a squall line will begin to affect northern
zones around midnight, with severe wind gusts possible. Left pops
alone for tonight for now, but major increases in pops may be
necessary (especially NE) after midnight, pending the track the
expected MCS takes.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 305 PM CDT Tue Jun 28 2016
For this evening, an outflow boundary will continue push south of
Dodge City, with some strong to severe storms possible. Hail to
quarter size and heavy rainfall possible. A supercell or two is also
possible with larger hail with some stronger upper winds today than
yesterday.
Then later tonight a Mesoscale Convective Complex (MCS)
is forecast to move in from Nebraska. Will carry highest chances
across south central sections then blend smaller chances west.
Severe storms are not expected later tonight, except for some strong
winds to 50 mph and small hail, lots of lightning and areas of heavy
rainfall. Overnight lows will be in the mid to upper 60s.
For Wednesday, upper level northwest flow will continue with a cold
front near the Oklahoma border. Will carry 20 to 30 percent chances
wtih the better chances south and east of Dodge City. South winds
shift to the east and northeast with a cold front. Highs look to be
from the upper 80s near and east of Dodge City with mid 90s for
parts of southwest Kansas.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 323 PM CDT Tue Jun 28 2016
For the period of Wednesday Night into next Tuesday, an active
northwest flow pattern continues into Thursday then begins to
flatten out with more shortwaves into Sunday. By Monday and into
Tuesday chances for rainfall become less as any jet stream features
shift north. Areas of thunderstorms are forecast daily with the best
chances mainly in the evenings and overnights into Sunday.
Highs will be cooler, with mainly lower to mid 80s into Sunday, then
warming to around 90 to 95 on Monday and Tuesday. Overnight lows
will be in the mid to upper 60s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 600 PM CDT Tue Jun 28 2016
Thunderstorms have ended temporarily across SW KS, but outflow
boundaries left over from previous storms will make winds variable
and erratic at the terminals early this evening. VFR will prevail
early tonight along with SE surface winds. A large thunderstorm
complex entering NW Nebraska at 23z will race SE overnight, with
model consensus suggesting it will begin to affect the terminals
during the 06-07z Wed timeframe. Primary impact from this complex
will be gusty outflow winds to near 50 kts. HRRR solution suggests
a weakening squall line will extend from near HYS to near GCK
during this timeframe, and used this as a first approximation for
TEMPO groups for convective wind gusts. Highest confidence on
impacts to aviation through Wednesday morning is at HYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 68 91 67 88 / 50 20 30 40
GCK 66 93 67 87 / 60 20 20 40
EHA 67 95 66 89 / 60 20 30 50
LBL 68 94 67 90 / 40 30 30 50
HYS 66 87 65 84 / 60 40 40 40
P28 69 90 69 90 / 30 30 40 50
&&
.DDC Watches/Warnings/Advisories...
NONE.
&&
$$
UPDATE...Turner
SHORT TERM...Kruse
LONG TERM...Kruse
AVIATION...Turner
Area Forecast Discussion
National Weather Service Phoenix AZ
528 AM MST WED JUN 29 2016
.UPDATE...To Aviation and Fire Weather Discussions...
&&
.SYNOPSIS...
High pressure will move somewhat north and east of Arizona this week
allowing warm temperatures to prevail, but also bring a couple of
weather disturbances through the state. An increase in monsoon
moisture will accompany these weather systems, providing a threat of
afternoon and evening showers and thunderstorms the remainder of
week. As moisture increases over south central Arizona, high
temperatures will fall with some locations dropping below 100
degrees on Friday. There will be a return to drier southwest flow
aloft over the weekend and into early next week which will limit
thunderstorms to higher terrain areas east of Phoenix by Sunday.
High temperatures will steadily climb late this week and early next
week as the atmosphere becomes drier.
&&
.DISCUSSION...
Strong high pressure aloft remained situated across the desert
southwest early this morning with the main high center located near
the four corners towards far north central Arizona. Typical
monsoonal circulation has been established with southeast flow
spreading increasing moisture westward across the lower deserts out
towards the lower Colorado River valley. At 2 am considerable
showers and isolated storms persisted in the Tucson area, with
scattered mostly light showers pushing westward across the
central/southwest deserts. Flow aloft is not especially
divergent/difluent and no significant inverted trof features are in
the area so much of the convection is likely being driven by
continued boundary interactions.
For the next few days the monsoonal circulation will remain in place
across the area keeping moisture flowing across the lower deserts.
Occasional minor disturbances will be embedded in the flow around
the high, helping to enhance thunderstorm development from time to
time, however for the most part upper wind fields do not appear to
be very strong over Arizona today through Friday. Mean 300-700mb
wind fields are mostly at or below 15 knots over most of the area,
and upper streamline fields tend to be more anticyclonic and
laminar, not exhibiting significant deformation or difluent fields.
With weaker winds and more modest support aloft, we will fall back
towards more of a typical diurnal and climo-based convective pattern
every day with the best chances for storms developing over higher
terrain then moving into the lower deserts overnight. Moisture does
look to be impressive however with PWAT values between 1.5 and 1.8
inches across most of the area from the lower Colorado River
eastward each day through Friday. One feature that the progs have
been trying to latch onto is an inverted trof the pushes north and
into south central Arizona Thursday night into the day Friday. As
this feature approaches and then moves across the area, PWAT value
climb to around 2 inches over portions of south central AZ. As such
we may see the potential for heavy rains developing at times
Thursday night into the day Friday. POPs have been raised 5-10
percent at times mainly Thursday and Friday to account for this with
chance numbers in place across most of the central deserts as well
as the higher terrain east of Phoenix. It is very possible that our
POPs will need further raising later this week.
With cloud cover and moisture increasing from east to west this
week, the temperature trends will be downward, with portions of the
central deserts falling well below seasonal normals by Friday.
However, there is one issue with expected heat and that will be over
the far western deserts and into southeast California today. With H5
heights around 594dm and the airmass still a bit on the dry side,
there is potential for some locations, especially the Imperial
valley, to reach or exceed 115 degrees today. Imperial reached 117
yesterday and we expect similar conditions today. There is potential
for debris clouds current over the AZ deserts to spread into SE
California today and cool things a bit but to be on the safe side we
will be issuing an Excessive Heat Warning for CAZ033 -Imperial
County - from 10 am until 8 pm today. It should cool below warning
thresholds tomorrow so this will be just a one day warning.
Despite copious moisture in place Friday over deserts east of the
lower Colorado River valley, upper streamlines and mean steering
winds are forecast to start turning to the south/southwest. This will
not dry out the area for Friday or Friday night, but this
directional shift in the winds will play a role for the extended
portion of the forecast. Guidance, including GEFS ensemble spaghetti
guidance, calls for weak troffing to develop over the PAC northwest
and along the central CA coast by Saturday and this will lead to
continued southwest steering flow and upper streamlines over the
weekend and into the first part of next week. We will see moisture
steadily decrease from west to east and by Sunday the
afternoon/evening thunderstorms will be confined to the higher
terrain areas east of Phoenix. We will then see mostly sunny or
sunny days and clear nights from Phoenix west during the latter
portion of the extended. As the airmass dries we can expect high
temperatures to climb back up to, and then above, seasonal normals.
By next Monday much of the lower deserts will see highs near or even
exceeding the 110 degree mark.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
Any remnant shower activity thru the early morning will stay well to
the W/SW of the Phx area terminals with BKN-OVC debris clouds also
clearing to the west. Morning winds to continue with their easterly
headings, with slight lower speeds than the outflow induced ones from
overnight. With skies clearing enough to provide heating and support
storm initiation this afternoon, will keep at least VCTS mention in
the TAFs for this evening, around 30/02z. Gusty outflow winds,
broadly from the east, are possible along with storm development
along outflow intrusions. Winds in the wake of outflow and storm
development will become more erratic, with several outflow/storm
wind interactions causing more variable headings.
Southeast California/Southwest Arizona including KIPL and KBLH:
Morning debris clouds from thundershower activity across AZ will
cross the CO River, generating SCT-BKN coverage AOA 12kft this
morning for both KIPL and KBLH. Little aviation impacts through
Wednesday afternoon with storms remaining well east of SE CA. While
surface winds will favor a south and southeasterly direction, outflow
boundaries from distant storms may cause abrupt wind shifts, or
variable winds overnight.
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Friday through Tuesday...
Humidities, dewpoints and storm chances will peak Friday before
trending downward through the late weekend. Elevated humidities and
dewpoints will linger for Saturday, with slight chances for storms holding
over the south-central AZ deserts and better chances for the higher
terrain north/east/southeast of Phoenix. Gradual drying trend will
commence Sunday and into early next week with lower desert minimum
humidities drier than 15 percent (and possibly lower) by Monday.
Thunderstorm chances will be confined to the higher terrain of
south-central AZ Sun-Tue and be only slight. Apart from strong
erratic winds associated with thunderstorms, southerly breeziness can
be expected over southwest AZ and southeast CA Thu-Sat(less so over
south-central AZ). Winds will favor southwesterly directions next
week.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...Excessive Heat Warning from 10 AM this morning to 8 PM PDT this
evening for CAZ033.
&&
$$
Visit us on Facebook...Twitter...and at weather.gov/phoenix
DISCUSSION...CB
AVIATION...Nolte
FIRE WEATHER...Nolte/AJ
Area Forecast Discussion
National Weather Service Phoenix AZ
528 AM MST WED JUN 29 2016
.UPDATE...To Aviation and Fire Weather Discussions...
&&
.SYNOPSIS...
High pressure will move somewhat north and east of Arizona this week
allowing warm temperatures to prevail, but also bring a couple of
weather disturbances through the state. An increase in monsoon
moisture will accompany these weather systems, providing a threat of
afternoon and evening showers and thunderstorms the remainder of
week. As moisture increases over south central Arizona, high
temperatures will fall with some locations dropping below 100
degrees on Friday. There will be a return to drier southwest flow
aloft over the weekend and into early next week which will limit
thunderstorms to higher terrain areas east of Phoenix by Sunday.
High temperatures will steadily climb late this week and early next
week as the atmosphere becomes drier.
&&
.DISCUSSION...
Strong high pressure aloft remained situated across the desert
southwest early this morning with the main high center located near
the four corners towards far north central Arizona. Typical
monsoonal circulation has been established with southeast flow
spreading increasing moisture westward across the lower deserts out
towards the lower Colorado River valley. At 2 am considerable
showers and isolated storms persisted in the Tucson area, with
scattered mostly light showers pushing westward across the
central/southwest deserts. Flow aloft is not especially
divergent/difluent and no significant inverted trof features are in
the area so much of the convection is likely being driven by
continued boundary interactions.
For the next few days the monsoonal circulation will remain in place
across the area keeping moisture flowing across the lower deserts.
Occasional minor disturbances will be embedded in the flow around
the high, helping to enhance thunderstorm development from time to
time, however for the most part upper wind fields do not appear to
be very strong over Arizona today through Friday. Mean 300-700mb
wind fields are mostly at or below 15 knots over most of the area,
and upper streamline fields tend to be more anticyclonic and
laminar, not exhibiting significant deformation or difluent fields.
With weaker winds and more modest support aloft, we will fall back
towards more of a typical diurnal and climo-based convective pattern
every day with the best chances for storms developing over higher
terrain then moving into the lower deserts overnight. Moisture does
look to be impressive however with PWAT values between 1.5 and 1.8
inches across most of the area from the lower Colorado River
eastward each day through Friday. One feature that the progs have
been trying to latch onto is an inverted trof the pushes north and
into south central Arizona Thursday night into the day Friday. As
this feature approaches and then moves across the area, PWAT value
climb to around 2 inches over portions of south central AZ. As such
we may see the potential for heavy rains developing at times
Thursday night into the day Friday. POPs have been raised 5-10
percent at times mainly Thursday and Friday to account for this with
chance numbers in place across most of the central deserts as well
as the higher terrain east of Phoenix. It is very possible that our
POPs will need further raising later this week.
With cloud cover and moisture increasing from east to west this
week, the temperature trends will be downward, with portions of the
central deserts falling well below seasonal normals by Friday.
However, there is one issue with expected heat and that will be over
the far western deserts and into southeast California today. With H5
heights around 594dm and the airmass still a bit on the dry side,
there is potential for some locations, especially the Imperial
valley, to reach or exceed 115 degrees today. Imperial reached 117
yesterday and we expect similar conditions today. There is potential
for debris clouds current over the AZ deserts to spread into SE
California today and cool things a bit but to be on the safe side we
will be issuing an Excessive Heat Warning for CAZ033 -Imperial
County - from 10 am until 8 pm today. It should cool below warning
thresholds tomorrow so this will be just a one day warning.
Despite copious moisture in place Friday over deserts east of the
lower Colorado River valley, upper streamlines and mean steering
winds are forecast to start turning to the south/southwest. This will
not dry out the area for Friday or Friday night, but this
directional shift in the winds will play a role for the extended
portion of the forecast. Guidance, including GEFS ensemble spaghetti
guidance, calls for weak troffing to develop over the PAC northwest
and along the central CA coast by Saturday and this will lead to
continued southwest steering flow and upper streamlines over the
weekend and into the first part of next week. We will see moisture
steadily decrease from west to east and by Sunday the
afternoon/evening thunderstorms will be confined to the higher
terrain areas east of Phoenix. We will then see mostly sunny or
sunny days and clear nights from Phoenix west during the latter
portion of the extended. As the airmass dries we can expect high
temperatures to climb back up to, and then above, seasonal normals.
By next Monday much of the lower deserts will see highs near or even
exceeding the 110 degree mark.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
Any remnant shower activity thru the early morning will stay well to
the W/SW of the Phx area terminals with BKN-OVC debris clouds also
clearing to the west. Morning winds to continue with their easterly
headings, with slight lower speeds than the outflow induced ones from
overnight. With skies clearing enough to provide heating and support
storm initiation this afternoon, will keep at least VCTS mention in
the TAFs for this evening, around 30/02z. Gusty outflow winds,
broadly from the east, are possible along with storm development
along outflow intrusions. Winds in the wake of outflow and storm
development will become more erratic, with several outflow/storm
wind interactions causing more variable headings.
Southeast California/Southwest Arizona including KIPL and KBLH:
Morning debris clouds from thundershower activity across AZ will
cross the CO River, generating SCT-BKN coverage AOA 12kft this
morning for both KIPL and KBLH. Little aviation impacts through
Wednesday afternoon with storms remaining well east of SE CA. While
surface winds will favor a south and southeasterly direction, outflow
boundaries from distant storms may cause abrupt wind shifts, or
variable winds overnight.
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Friday through Tuesday...
Humidities, dewpoints and storm chances will peak Friday before
trending downward through the late weekend. Elevated humidities and
dewpoints will linger for Saturday, with slight chances for storms holding
over the south-central AZ deserts and better chances for the higher
terrain north/east/southeast of Phoenix. Gradual drying trend will
commence Sunday and into early next week with lower desert minimum
humidities drier than 15 percent (and possibly lower) by Monday.
Thunderstorm chances will be confined to the higher terrain of
south-central AZ Sun-Tue and be only slight. Apart from strong
erratic winds associated with thunderstorms, southerly breeziness can
be expected over southwest AZ and southeast CA Thu-Sat(less so over
south-central AZ). Winds will favor southwesterly directions next
week.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...Excessive Heat Warning from 10 AM this morning to 8 PM PDT this
evening for CAZ033.
&&
$$
Visit us on Facebook...Twitter...and at weather.gov/phoenix
DISCUSSION...CB
AVIATION...Nolte
FIRE WEATHER...Nolte/AJ
[top]
Area Forecast Discussion
National Weather Service Tucson AZ
428 AM MST WED JUN 29 2016
.SYNOPSIS...Expect scattered to numerous showers and thunderstorms
through Friday. Locally heavy rainfall will occur during this period.
A gradual drying trend will then begin Saturday and continue into
early next week. However, enough moisture will remain for a slight
chance of showers and thunderstorms east of Tucson next Monday and
Tuesday. Cooler temperatures will occur, especially Friday, then a
warmer temperatures will return early next week.
&&
.DISCUSSION...Scattered showers and isolated thunderstorms were
occurring from the Tohono O`Odham Nation eastward across eastern
Pima County, Santa Cruz County and into western Cochise County at
this time. The areal coverage and individual cell intensities have
been gradually decreasing during the past hour. IR/Water vapor
satellite imagery depicted decaying Mesoscale Convective Complexes
over the eastern portion of southeast Arizona, and further south
over central/southern Sonora Mexico.
The MCS over southeast Arizona produced rainfall amounts during the
overnight hours generally ranging from 0.25 - 0.75 inch across the
northern portion of the Tucson metro area, including the Catalina
Mountains, and further east over northwest Cochise County including
Benson. Within this area, rainfall amounts to around 1.75 inches
were measured. Meanwhile, rainfall amounts further south from the
southern portion of the Tucson metro area into Santa Cruz/southwest
Cochise County generally ranged from 0.10 - 0.50 inch, with locally
heavier amounts to around 1.00 inch.
The forecast challenge for today will be the role of the ongoing
precipitation area, and the extent of cloud cover into mid-morning
regarding the potential re-generation of showers/thunderstorms later
today. Although several theoretical scenarios abound, only one
scenario will eventually become, and ultimately be, reality.
Having written that, am leaning toward the scenario suggested by a
combination of several HRRR solutions and the 29/00Z Univ. of AZ WRF-
NAM. Thus, believe that showers/tstms will continue to gradually
decrease in coverage during the next several hours. Am expecting the
bulk of any rainfall of significance to end around 15Z-17Z, with the
Tucson metro area perhaps being the last area to become precip-free.
Am then expecting clouds to decrease sufficiently late this morning,
or by noon, to allow for the showers/tstms to develop during the
early afternoon hours, particularly south of Tucson. A fairly deep
ely flow should then promote a westward migration of showers/tstms
into central/wrn Pima County late this afternoon and evening.
For this forecast issuance, PoPs were raised for most sections this
afternoon and evening, and especially across western locales. Thus,
am expecting scattered to numerous showers/tstms this afternoon and
evening followed by low-end chance-category PoPs, or scattered
coverage of showers/tstms across much of the area late tonight.
29/00Z GFS/ECMWF/CMC remained in good agreement regarding the
potential for a widespread precip evening Thur-Fri. Ample moisture
Thursday with precip water values progged via the GFS by 01/00Z
ranging from 1.0 inch across the White Mountains to around 2.0
inches across western Pima County will be in place. Meanwhile,
although generally weak sely mid-level flow will be present, the NWP
models depict an inverted trough to move northward into southern AZ
Thur night, then continue northward into central AZ Friday.
Per coordination with neighboring WFO`s, PoPs were generally trended
higher about 5-15 percent or so during the Thur-Fri period. These
values translate into scattered to numerous showers/tstms, with the
greatest coverage expected to occur across central/ern sections.
Would not be surprised to eventually see an MCS over this forecast
area Thursday night. Friday then holds the potential for fairly
widespread coverage of light-to-moderate showers with embedded
thunderstorms.
26/00Z GFS/ECMWF/CMC remained similar versus previous solutions in
depicting deep moisture over the area Friday to be shunted eastward
into New Mexico Saturday, as generally wly flow becomes established
over the area. Thus, a gradual decrease in showers/tstms will start
Saturday followed by a decrease in daily coverage Sunday-Tuesday.
In summary, expect isolated to perhaps scattered showers/tstms
Sunday, then only a slight chance of showers/tstms limited to
locales east of Tucson Monday. By next Tuesday, a slight chance of
showers/tstms exists mainly east of a Mount Graham-Benson line, and
particularly across the White Mountains. Thereafter, the focus of
attention will turn toward a tropical system that is progged to pass
well to the southwest of southern Baja California by the middle of
next week.
A gradual daily cooling trend will occur today into Friday, and
high temps Friday will be well below seasonal normals. A warming
trend is on tap Saturday-Monday, with near normal daytime temps to
return Monday-Tuesday.
&&
.AVIATION...VALID THRU 30/12Z.
Showers and thunderstorms over and south of KTUS will gradually
diminish through the morning hours with local MVFR conditions
possible near some heavy rainers, otherwise VFR conditions with
plenty of debris clouds around. Debris clouds to diminish later
this morning with scattered thunderstorms developing again near the
higher terrain this afternoon. Wind speeds generally less than 12
kts except 30-35 kts in and around stronger thunderstorms. Aviation
discussion not updated for TAF amendments.
&&
.FIRE WEATHER...With plenty of moisture and instability around there
will be daily rounds of scattered showers and thunderstorms through
Friday. The strongest storms will be capable of very strong winds
and heavy downpours especially during the mid afternoon to early
evening hours. Would expect that by Friday nearly every location in
SE AZ will have had at least one round of rainfall and with high
dewpoints humidity levels will remain high continuing the fuel
moistening trend.
Atmospheric moisture will begin to diminish across the region
Saturday onward resulting in a decrease in the amount of convection
each day. By Monday and Tuesday any isolated convection will be
limited to the mountains near the eastern border and over the White
Mountains.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
DISCUSSION...Francis
AVIATION/FIRE WEATHER...Cerniglia
Area Forecast Discussion
National Weather Service Flagstaff AZ
330 PM MST WED JUN 29 2016
.SYNOPSIS...Shower and thunderstorm activity will increase over the
next few days as a moist southerly flow develops across Arizona.
Expect storms each day with the best potential for heavy rain
on Thursday and Friday.
&&
.DISCUSSION...Very active day across northern Arizona today with
thunderstorms, heavy rain, and local minor flooding issues. It will
remain active this evening and then decrease after dark.
For Thursday through Saturday...Southerly flow will deliver deep
moisture with widespread showers and thunderstorms. The deepest
moisture will be south of the Mogollon Rim southward where storms
will be the most numerous. However, anywhere across northern Arizona
could see strong storms through Saturday. Any storm could produce
hail, strong winds, heavy rain, and flash flooding.
From Sunday onward...A drier and stabilizing westerly flow
develops. Most areas across northern Arizona will see only a
slight chance of showers and storms. The only exception will be
the mountain areas along the Arizona/New Mexico border where
lingering moisture will result in scattered storms.
&&
.AVIATION...For the 00Z Package...Scattered to numerous TSRA
expected to develop today with the focus of activity over the higher
terrain of northern AZ. Locally heavy rain, small hail, and gusty
winds possible with storms. Coverage of showers and thunderstorms
will decrease overnight, then increase again after 18Z Friday.
Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...An active monsoon weather pattern will continue
through the week with scattered to numerous showers and
thunderstorms each day. An increase in moisture will raise the
threat for heavy rain by Thursday and Friday. Gusty outflow winds
also possible near any shower or storms.
Saturday through Monday...Active monsoon weather continues through
Saturday with close to average temperatures. A downturn in
thunderstorm activity is possible by Sunday or early next week.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...MAS
AVIATION...JJ
FIRE WEATHER...JJ
For Northern Arizona weather information visit
weather.gov/flagstaff
Area Forecast Discussion
National Weather Service Flagstaff AZ
330 PM MST WED JUN 29 2016
.SYNOPSIS...Shower and thunderstorm activity will increase over the
next few days as a moist southerly flow develops across Arizona.
Expect storms each day with the best potential for heavy rain
on Thursday and Friday.
&&
.DISCUSSION...Very active day across northern Arizona today with
thunderstorms, heavy rain, and local minor flooding issues. It will
remain active this evening and then decrease after dark.
For Thursday through Saturday...Southerly flow will deliver deep
moisture with widespread showers and thunderstorms. The deepest
moisture will be south of the Mogollon Rim southward where storms
will be the most numerous. However, anywhere across northern Arizona
could see strong storms through Saturday. Any storm could produce
hail, strong winds, heavy rain, and flash flooding.
From Sunday onward...A drier and stabilizing westerly flow
develops. Most areas across northern Arizona will see only a
slight chance of showers and storms. The only exception will be
the mountain areas along the Arizona/New Mexico border where
lingering moisture will result in scattered storms.
&&
.AVIATION...For the 00Z Package...Scattered to numerous TSRA
expected to develop today with the focus of activity over the higher
terrain of northern AZ. Locally heavy rain, small hail, and gusty
winds possible with storms. Coverage of showers and thunderstorms
will decrease overnight, then increase again after 18Z Friday.
Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...An active monsoon weather pattern will continue
through the week with scattered to numerous showers and
thunderstorms each day. An increase in moisture will raise the
threat for heavy rain by Thursday and Friday. Gusty outflow winds
also possible near any shower or storms.
Saturday through Monday...Active monsoon weather continues through
Saturday with close to average temperatures. A downturn in
thunderstorm activity is possible by Sunday or early next week.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...MAS
AVIATION...JJ
FIRE WEATHER...JJ
For Northern Arizona weather information visit
weather.gov/flagstaff
[top]
Area Forecast Discussion
National Weather Service Tucson AZ
300 PM MST WED JUN 29 2016
.SYNOPSIS...Expect scattered to numerous showers and thunderstorms
through Friday. Locally heavy rainfall will occur during this period.
A gradual drying trend will then begin Saturday and continue into
early next week. However, enough moisture will remain for a slight
chance of showers and thunderstorms east of Tucson next Monday and
Tuesday. Cooler temperatures will occur, especially Friday, then
warmer temperatures will return early next week.
&&
.DISCUSSION...After debris cloudiness cleared this morning, it
didn`t take much to get our storms going early this afternoon. This
is in part due to the very moist airmass in place, with surface
dewpoints holding steading in the upper 50s and lower 60s for most
locations. Latest SPC mesoanalysis indicates in excess of 1500 J/kg
of SBCAPE and little to no CIN over much of southeast Arizona. As
such, scattered strong to potentially severe thunderstorms are
currently ongoing, especially across Santa Cruz and eastern Pima
counties.
CIRA total LPW amounts valid 29/21Z ranged from 1.3 inches across
Cochise county to near 2 inches across western Pima county. That
said, am still concerned about some heavy rainers through this
evening and areas of flash flooding should some of the same spots
that got hit last night get hit again this afternoon. For example,
with its first storm of the day, KOLS picked up nearly 1 inch of
rainfall in less than an hour, and KTUS has now broken its 1-day
rainfall record previously set in 1912 at 0.55 inches. Latest dual-
pol rainfall storm totals are ranging from 0.5 inches to over 1.5
inches in a few locations, especially since storms are barely moving
and mainly playing off of one another`s outflows or hugging terrain.
Expect convection to continue through this evening with overnight
showers/embedded thunderstorms not out of the question.
The Thursday/Friday forecast continued to look good with regard to
the 29/12z suite of NWP models, so not too many changes were made to
the official forecast. Still expecting plenty of moisture to be
hanging around, thanks to a modest surge from the Gulf of
California. PWAT values across western Pima county could exceed 2
inches from Thursday morning into Friday afternoon. Weak sly to sely
steering flow will occur both days as the upper high meanders east
into New Mexico and then southeast into west Texas. The GFS is
trying to bring a nice little vorticity maximum across eastern zones
Thursday night into Friday morning, so cannot rule out an overnight
MCS of sorts. Friday then holds the potential for fairly widespread
coverage of light-to-moderate showers with embedded thunderstorms.
Shower and storm coverage will then take a downturn into Saturday
and Sunday as drier wly flow becomes established over the area.
Expect a gradual decrease in precip coverage from west to east from
Sunday to Wednesday. Thereafter, will turn our focus toward a
tropical system that is progged to pass well to the southwest of
southern Baja California by the middle of next week for any
potential moisture surge.
A gradual daily cooling trend will occur into Friday, and high temps
Friday will be well below seasonal normals. We will then warm back
up into early next week, with near normal daytime temps Monday-
Wednesday.
&&
.AVIATION...VALID THRU 31/00Z.
Showers and thunderstorms will be in the vicinity of terminals
through at least 30/03Z. Another round of convection will be
possible overnight after 30/06Z. Gusty winds and brief MVFR
conditions in heavy rainfall are likely. Wind gusts could exceed 45
kts. Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...With plenty of moisture and instability around there
will be daily rounds of scattered showers and thunderstorms through
Friday. The strongest storms will be capable of very strong winds
and heavy downpours especially during the mid afternoon to early
evening hours. Would expect that by Friday nearly every location in
SE AZ will have had at least one round of rainfall and with high
dewpoints humidity levels will remain high continuing the fuel
moistening trend.
Atmospheric moisture will begin to diminish across the region
Saturday onward resulting in a decrease in the amount of convection
each day. By Monday and Tuesday any isolated convection will be
limited to the mountains near the eastern border and over the White
Mountains.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
DISCUSSION...French
AVIATION/FIRE WEATHER...Cantin
Area Forecast Discussion
National Weather Service Tucson AZ
300 PM MST WED JUN 29 2016
.SYNOPSIS...Expect scattered to numerous showers and thunderstorms
through Friday. Locally heavy rainfall will occur during this period.
A gradual drying trend will then begin Saturday and continue into
early next week. However, enough moisture will remain for a slight
chance of showers and thunderstorms east of Tucson next Monday and
Tuesday. Cooler temperatures will occur, especially Friday, then
warmer temperatures will return early next week.
&&
.DISCUSSION...After debris cloudiness cleared this morning, it
didn`t take much to get our storms going early this afternoon. This
is in part due to the very moist airmass in place, with surface
dewpoints holding steading in the upper 50s and lower 60s for most
locations. Latest SPC mesoanalysis indicates in excess of 1500 J/kg
of SBCAPE and little to no CIN over much of southeast Arizona. As
such, scattered strong to potentially severe thunderstorms are
currently ongoing, especially across Santa Cruz and eastern Pima
counties.
CIRA total LPW amounts valid 29/21Z ranged from 1.3 inches across
Cochise county to near 2 inches across western Pima county. That
said, am still concerned about some heavy rainers through this
evening and areas of flash flooding should some of the same spots
that got hit last night get hit again this afternoon. For example,
with its first storm of the day, KOLS picked up nearly 1 inch of
rainfall in less than an hour, and KTUS has now broken its 1-day
rainfall record previously set in 1912 at 0.55 inches. Latest dual-
pol rainfall storm totals are ranging from 0.5 inches to over 1.5
inches in a few locations, especially since storms are barely moving
and mainly playing off of one another`s outflows or hugging terrain.
Expect convection to continue through this evening with overnight
showers/embedded thunderstorms not out of the question.
The Thursday/Friday forecast continued to look good with regard to
the 29/12z suite of NWP models, so not too many changes were made to
the official forecast. Still expecting plenty of moisture to be
hanging around, thanks to a modest surge from the Gulf of
California. PWAT values across western Pima county could exceed 2
inches from Thursday morning into Friday afternoon. Weak sly to sely
steering flow will occur both days as the upper high meanders east
into New Mexico and then southeast into west Texas. The GFS is
trying to bring a nice little vorticity maximum across eastern zones
Thursday night into Friday morning, so cannot rule out an overnight
MCS of sorts. Friday then holds the potential for fairly widespread
coverage of light-to-moderate showers with embedded thunderstorms.
Shower and storm coverage will then take a downturn into Saturday
and Sunday as drier wly flow becomes established over the area.
Expect a gradual decrease in precip coverage from west to east from
Sunday to Wednesday. Thereafter, will turn our focus toward a
tropical system that is progged to pass well to the southwest of
southern Baja California by the middle of next week for any
potential moisture surge.
A gradual daily cooling trend will occur into Friday, and high temps
Friday will be well below seasonal normals. We will then warm back
up into early next week, with near normal daytime temps Monday-
Wednesday.
&&
.AVIATION...VALID THRU 31/00Z.
Showers and thunderstorms will be in the vicinity of terminals
through at least 30/03Z. Another round of convection will be
possible overnight after 30/06Z. Gusty winds and brief MVFR
conditions in heavy rainfall are likely. Wind gusts could exceed 45
kts. Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...With plenty of moisture and instability around there
will be daily rounds of scattered showers and thunderstorms through
Friday. The strongest storms will be capable of very strong winds
and heavy downpours especially during the mid afternoon to early
evening hours. Would expect that by Friday nearly every location in
SE AZ will have had at least one round of rainfall and with high
dewpoints humidity levels will remain high continuing the fuel
moistening trend.
Atmospheric moisture will begin to diminish across the region
Saturday onward resulting in a decrease in the amount of convection
each day. By Monday and Tuesday any isolated convection will be
limited to the mountains near the eastern border and over the White
Mountains.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
DISCUSSION...French
AVIATION/FIRE WEATHER...Cantin
[top]
Area Forecast Discussion
National Weather Service Phoenix AZ
252 PM MST WED JUN 29 2016
.UPDATE...To Aviation and Fire Weather Discussions...
&&
.SYNOPSIS...
An increase in monsoon moisture will bring chances for showers and
thunderstorms the remainder of week. As moisture increases over south
central Arizona, high temperatures will fall with some locations
dropping below 100 degrees on Friday. There will be a return to drier
southwest flow aloft over the weekend and into early next week which
will limit thunderstorms to higher terrain areas east of Phoenix by
Sunday. High temperatures will steadily climb late this week and
early next week as the atmosphere becomes drier.
&&
.DISCUSSION...
Rest of today...
Debris cloudiness has kept portions of our forecast area significantly
cooler than yesterday - most noticeably over Yuma county where
cloudiness was thicker. Temperatures have also been lower further
west where there has been full sun but with high dew points.
However, that means muggy conditions. In fact, in the Imperial Valley
some heat index readings have already reached 110. Thus, held on to
Excessive Heat Warning for Imperial County. The Gulf surge
responsible for the low level moist advection over southwest AZ and
far SE Ca has weakened considerably though southerly winds continue
through about 5 kft per KYUX wind profile data. Storm activity has
begun in the usual places early this afternoon - even over southeast
Arizona where cloud cover had been inhibiting surface heating. SPC
mesoanalysis for 20Z has high CAPE values over southeast AZ
extending into central AZ. There is another bullseye over Imperial
County but CIN values are highest there as well. This suggests
potential for storms to produce both strong winds and localized heavy
rain. The latter more so for southeast AZ. Experience indicates that
the SPC automated mesoanalysis tends to be overly optimistic.
Hi-res models are a mixed bag in terms of how they depict storm
activity for our forecast area today/tonight. Our local WRF-ARW and
the UofA WRF-GFS are the most aggressive as they depict storms to the
north and south of Phoenix producing outflow and subsequent right
over the metro. The latest HRRR depicts storms moving westward from
Gila County and eastern Pinal but struggling to propagate over the
lower deserts. Even that is somewhat of an uptick compared to
previous runs. Larger scale models are also not all that enthusiastic
(except for Canadian/GEM). It`s not surprising given the cooler
boundary layers and a bit of warming above 500mb. They are all
reluctant to depict storm activity west of the Lower Colorado River
Valley (except for latest HRRR which may be initializing some
isolated convection over the Baja mountains south of the Mexico
border). However, there is sufficient CAPE for storms over the higher
terrain and associated outflows. Thus in turn there is potential for
storms (mainly east of the Lower Colorado River Valley). Also, there
is an inverted wave in the mid levels slowly moving westward across
Arizona.
Thursday and Friday...
Much of what happens Thursday will be predicated on what happens
tonight. There is good agreement on something of a classic monsoon
flow with a southerly component to the steering flow and the presence
of deep moisture (e.g. 1000-700mb mean mixing ratios of 10-12 g/kg).
If activity turns out to be quiet tonight then that would bode well
for better destabilization Thursday. The converse would be true for
an active night tonight. The inverted trough/wave appears to break up
with a portion of it slowly tracking northward through AZ during the
day Thursday followed by the other piece Thursday night. It is unclear
what kind of contribution this will have. On Friday, deep moisture
will be in place but the steering flow takes on a westerly component.
With the moisture and debris clouds, temps continue to trend
downward - even dipping below normal over south-central AZ.
Saturday through Wednesday...
Guidance, including GEFS ensemble spaghetti guidance, calls for weak
troffing to develop over the PAC northwest and along the central CA
coast by Saturday and this will lead to continued southwest steering
flow over the weekend and into the first part of next week. We will
see moisture steadily decrease from west to east and by Sunday the
afternoon/evening thunderstorms will be confined to the higher
terrain areas east of Phoenix. We will then see mostly sunny or sunny
days and clear nights from Phoenix west during the first half of next
week. As the airmass dries we can expect high temperatures to climb
back up to, and then above, seasonal normals. By next Monday much of
the lower deserts will see highs near or even exceeding the 110
degree mark with little change Tue-Wed.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
Anticipate south/southeasterly surface winds to last for much of the
day with westerly winds struggling to develop this afternoon.
Thunderstorms will continue to develop north through southeast of
the Phoenix metro through 00Z, with outflows from distant storms
likely affecting some portions of the Phoenix metro this evening,
most likely after 01Z. Confidence in exact temporal and areal
coverage precludes a TEMPO or prevailing TSRA group, however, the
TAFs do reflect the scenario of nearby storms causing gusty outflow winds
primarily from the east this evening. We will be monitoring the situation
closely this evening and appropriate TAF amendments will be taken.
There are some indications that lingering shower/storm activity could
continue through late this evening, so will keep VCSH after 30/09Z.
Debris clouds will linger well past sunrise, with light southeasterly
surface winds.
Southeast California/Southwest Arizona including KIPL and KBLH:
Surface winds will favor south and southeasterly directions through
the TAF period, with a few gusts up to 20kts. Expect scattered to
broken high clouds to remain through the period. Although
thunderstorms should stay well east/southeast of the area, cannot
rule out an outflow from distant thunderstorms causing abrupt wind
shifts with some gustiness overnight.
Aviation discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Saturday through Wednesday...Enhanced humidities and storm chances
will continue on Saturday before trending downward, with minimum
humidities in the lower deserts ranging from 20-30 percent on
Saturday to 10-20 percent on Wednesday. Similarly, overnight
recoveries will also be trending downward as we start to dry out
this weekend. Thunderstorm chances on Saturday will be greatest
north, east, and southeast of Phoenix. Sunday through Wednesday,
thunderstorm chances will greatly decrease and be confined to the
higher terrain of south-central AZ. Apart from strong erratic winds
associated with thunderstorms, winds will primarily have a southerly
component in southeast California and southwest Arizona through the
period with some afternoon gustiness up to 20 mph. Over south-central
Arizona, winds will following typical upslope and downslope
directions with winds around 5 to 15 mph.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...Excessive Heat Warning until 8 PM PDT this evening for CAZ033.
&&
$$
Visit us on Facebook...Twitter...and at weather.gov/phoenix
DISCUSSION...AJ/CB
AVIATION...Hernandez
FIRE WEATHER...Hernandez