Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 06/30/16

Area Forecast Discussion
National Weather Service Phoenix AZ
850 PM MST WED JUN 29 2016

.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...
Scattered storms have been percolating through much of southern and
central Arizona this afternoon and early evening tied to rich
moisture profiles, adequate instability, and broad synoptic ascent
structures. 00Z KTWC sounding sampled excellent 11-12 g/kg boundary
layer moisture profiles with total column Pwats above 1.50 inches
and MLcape approaching 1500 J/kg. Though the KPSR sounding failed,
objective analysis suggests 10-11 g/kg and Mlcape closer to 1000
J/kg, and current radar returns support this analysis. Thus far,
lift has been mainly along better outflow boundaries and through
orographic ascent, though this may be rapidly changing.

Per objective analysis, dynamical fields are improving with a
distinct H7 trough passing into central AZ and upper difluence
becoming more pronounced. Radar loops reflect this improving
convective environment with organized deeper outflow and hints of an
MCV propagating through Gila County. This added lift along with
colliding outflow boundaries through the Phoenix metro may allow
more numerous storms to form mid to late evening. This is already
starting to become evident in radar imagery. Made some modest
adjustments to pops given current radar trends, and may need to
increase values further over the metro while also extending better
chance beyond midnight.

.PREVIOUS DISCUSSION...
/252 PM MST WED JUN 29 2016/
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:
Numerous outflow boundaries will continue to yield frequently
shifting winds through the evening and overnight, though eventually
storms to the east should allow for a stronger easterly gradient.
Still have held the VCTS mention into terminal sites as environment
is favorable for storms. Confidence on coverage and specific direct
impact to airfields is low.

Several high resolution models suggest showers re-entering the
picture very late tonight and Thursday morning with cigs falling
below 8K ft, but yet staying above 6K ft. Regardless of Shra
potential, it appears some measure of these cigs are probable with
an easterly wind component predominating.

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 20kt while only sct mid/high
clouds pass through the area tonight. Somewhat lower scattered
clouds will be possible Thursday. 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...None.

&&

$$

Visit us on Facebook...Twitter...and at weather.gov/phoenix

DISCUSSION...MO/AJ/CB
AVIATION...MO
FIRE WEATHER...Hernandez



  [top] 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
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
AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
447 PM PDT WED JUN 29 2016 .SYNOPSIS... A slight chance of thunderstorms and showers in the San Gabriel mountains into this evening. Breezy winds for Santa Barbara... Ventura and Los Angeles mountains and deserts into Thursday. Above normal temperatures and the overnight marine layer will persist into next week. The increasing onshore flow will spread the marine layer and bring a cool down for this weekend. The high should roll back in by Monday for a gradual warmup for next week. && .SHORT TERM...(TDY-SAT) Elevated instability indexes combined with relatively high residual moisture led to adding a slight chance of thunderstorms to the San Gabriel Mountains for late this afternoon and evening. A few cumulus have popped up over the area already though the best timing for the instability will be closer to 5 pm. Am not expecting much precipitation to develop but a lightning strike or two along with gusty winds could be a problem so is something to watch. Northwest to northerly winds will be gusty through the mountains and across the south coast of Santa Barbara County tonight. Winds will shift to the northeast late then diminish. Afternoon temperatures are a mixed bag today with some coastal and adjacent valley locations a few degrees warmer than yesterday and some a few degrees cooler. Sunny skies but a stronger onshore flow are the primary competing weather forces in the tug of war and the continued higher than normal humidity has added to the sluggishness of either a warmer or cooler trend. Regardless... temperatures are in the forecast ball park and the trend from today will be cooler and drier into the weekend. Helping that cooling trend along will be a strengthening onshore flow. It will continue to strengthen through the end of the week and the marine incursion will likely make it into the adjacent valleys by Friday morning if not for a period on Thursday. && .SHORT TERM...(TDY-SAT) .LONG TERM...(SUN-WED) Afternoon temperatures will bottom out on Saturday and Sunday as a relatively strong onshore flow brings the marine incursion into the coastal adjacent valleys and the cloud cover lingers well into the morning. What happens next remains a bit uncertain - in particular whether temperatures trend warmer slowly or quickly. The current forecast package trends slowly but definitely warmer. There remains a hint of further cooling instead but that would be a happy turn of events if it occurs. The monsoonal moisture does not retreat very far to the east and looks to remain close to the California / Arizona border for at least the next week. Therefore humidity levels should be slightly higher for the period with a possibility of a return to stickiness of the pattern shifts much. && .AVIATION...29/2345Z... At 2300Z, at KLAX, the marine layer depth was 1200 feet. The top of the inversion was at 2900 feet with a temperature of 29 degrees Celsius. With a shallow marine layer topped by a strong inversion, clearing has been difficult for portions of the immediate coast this afternoon. High confidence in 00z TAFS with ifr/lifr cigs returning to most coastal TAF locations tonight. With a slight deepening of the marine layer expected, look for some vsby restrictions into some of the coastal valleys on Thursday morning, including KBUR and KVNY. Otherwise, moderate uddfs and llws expected this evening vcnty KSBA due to sundowner winds in the nearby foothills. KLAX...High confidence in 00Z TAF. IFR cigs expected to return this evening, and persist into early Thursday morning. There is a 30 percent chance of marine clouds returning plus or minus two hours or more from time in forecast. KBUR...Moderate confidence in 00Z TAF. Mostly VFR conditions through period, except MVFR vsbys in haze on Thursday morning. There is a 20 percent chance of LIFR/IFR cigs sneaking into the airfield early Thursday morning. && .MARINE...29/200 PM... For the Outer Waters, good confidence in the current forecast. SCA level winds will continue through tonight. From Thursday through the weekend, the northwest winds will be a bit weaker, but there will still be a 30 percent chance of SCA level winds developing each afternoon and evening. For the Inner Waters, good confidence in the current forecast. Overall, winds and seas are expected to remain below SCA levels through the weekend. However, there is a slight chance of gusts reaching SCA levels this afternoon/evening across the waters north of Point Sal. Patchy dense fog in the coastal waters will be possible in the overnight and morning hours tonight and again Wednesday night. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Beach Hazards Statement in effect through Friday evening For zones 40-41-87. (See LAXCFWLOX). PZ...Small Craft Advisory in effect until 3 AM PDT Thursday For zones 670-673-676. (See LAXMWWLOX). && $$ PUBLIC...KJ AVIATION...Gomberg MARINE...Sweet SYNOPSIS...Seto weather.gov/losangeles
  [top] Area Forecast Discussion National Weather Service Sacramento CA 349 PM PDT WED JUN 29 2016 .SYNOPSIS... Hot and mainly dry weather this week. Isolated late day thunderstorms possible over the mountains. && .DISCUSSION... High pressure continues to be the predominant weather pattern across interior northern California. Temperatures, as of this afternoon, are running a few degrees cooler compared to 24 hours ago. Delta breeze should bring some cooling overnight, with lows in the mid 50s in the Delta, and upper 50s to low 60s near the Sacramento area. Light easterly flow overnight may drift smoke from the Trailhead fire down into the Auburn area. Cooling trend is expected late this week, as an upper trough develops along the Pacific Northwest. Saturday`s highs should be around the mid 90s in the Valley, except for a few triple digits in the northern Sacramento Valley. Model guidance suggest monsoonal moisture making its way northward along the Sierra crest late this week. Isolated storms may be possible mainly south of Lake Tahoe and east of the Sierra crest. A few late day afternoon thunderstorms may be possible along the Coastal Range late this week, as some instability might be present. && .EXTENDED DISCUSSION (Sunday THROUGH Wednesday) A weak upper trough will persist over the Pacific Northwest over the weekend into early next week with subtle cyclonic flow over NorCal, resulting in dry weather and near normal temperatures. Expect high temperatures in the 90s across the Valley, with 70s and 80s over the mountains. JClapp/Dang && .AVIATION... VFR conditions the next 24 hours. Light winds generally below 10 kts, except occasional SW wind gusts near the Delta region. The Delta Breeze should increase this afternoon and evening. JClapp/Dang && .STO Watches/Warnings/Advisories... None. && $$
  [top] Area Forecast Discussion National Weather Service Eureka CA 318 PM PDT WED JUN 29 2016 .SYNOPSIS...An upper level ridge will maintain hot and dry weather across northern California today. A trough will settle over the Pacific Northwest late this week causing inland temperatures to fall to near normal values. Coastal areas will remain seasonal with morning cloudiness. && .DISCUSSION... .SHORT TERM... (Tonight and Tomorrow) Similar to the last few days, morning stratus and patchy fog took its time to burn off through the early afternoon. We expect this theme to once again develop overnight near the coast and along the Eel River Valley. Otherwise, visible satellite imagery shows some agitated cumulus developing near the Trinity Alps, with the latest SPC mesoanalysis showing some weak instability, with SBCAPES occasionally topping out near or slightly above 250 J/kg. This is far less than model soundings (which shoed around 1600 J/KG), and water vapor imagery shows abundant dry air aloft. However, given the agitated cumulus, and precipitable water values marginally sufficient (currently near 0.6 inches per mesoanalysis), there is a non-zero chance for a shower/storm to develop. After coordinating with the Medford Forecast Office, we decided to add isolated thunder to the forecast for northern portions of Trinity County. Lows tonight will be near seasonal values for most locations. More of the same is in store for the area tomorrow, as morning coastal stratus/patchy fog will dissipate by early afternoon. A shortwave trough will begin to approach the region, allowing mid- level heights to drop some. This decrease in the heights will allow instability to increase somewhat, and considering ascent associated with the incoming trough may interact with the better instability, we maintained isolated thunder for the Trinity Horn tomorrow. Tempertures will once again warm into the 90s for our interior valleys, with a few locations making a run at the century mark. .LONG TERM... A cooling trend will develop over the next few days, mainly for the interior valleys. A weak trough aloft will move over the region for the end of the work week and persist through the weekend, possibly into early next week. This will allow for a continued decrease in heights in the lower to middle levels of the atmosphere. Similar to what was mentioned above, not too much change will be seen along the coast. Further inland though, look for afternoon highs to drop back into the upper 80s to mid 90s range. While the trough would make one think there could be increased precipitation potential, this won`t be the case. Northwest California will remain south of the jet stream, keeping the better sources of lift displaced from our area. The more likely scenario is for a diurnal increase in cumulus development, with temperatures remaining near seasonal values. /PD && .AVIATION...The 2145z (2:45 PM) Sat Pic showed stratus had eroded from many areas of the North Coast, although just north of ACV to CEC cigs around BKN010 still dominated. Cigs also continued around the Eel River Delta. North of CEC was clear with the CEC airport tethering on SCTvBKN as a weak eddy seemed to be affecting the airport: clouds on the southern periphery were broken and although basic winds have been north-westerly, the airport continued to get southerly breezy winds. Inland airfields will remain VFR-mostly sunny, except near the Trinity Horn and the Yolla Bolla`s where some scattered cumulus will continue through the afternoon. For the remainder of the taf period, marine clouds will re-intensify at much of the coast and near coastal inland areas from late afternoon through evening. /TA && .MARINE...Strong northerly winds and large steep seas will continue across the outer waters through Friday as high pressure offshore interacts with a thermal trough over the California interior. A GALE WARNING remains in effect for the outer waters through Friday evening. Conditions will be marginal for a warning on Saturday with gusts to 35 kt expected. Seas will likely remain very steep and rough on Saturday and near GALE conditions are anticipated in the outer waters, 10-60nm from shore, on Saturday. Northerly winds should start to ease below GALE Sunday into Monday, however, seas will continue to be steep with northerly breezes of 15 to 25 kt. Closer to shore and inside 10nm, primary concern tonight through Friday will be very steep waves. Northerly winds will howl around PT ST GEORGE, with gusts to 40KT each afternoon and evening through Thu. Even around Cape Mendocino, GALE FORCE winds are expected tonight into Thu. Northerly wind waves from the NWPS have been very close compared to the buoy observations over the last couple of days. Short period seas are expected to reach 10 ft or more tonight north of the Cape and inside 10nm. Therefore, the HAZARDOUS SEAS WATCH has been upgrade to a HAZARDOUS SEAS WARNING. Short period wind waves may subside below 10 feet by mid morning Thu, but are expected to increase to 10 ft or more again Thu afternoon and evening as north winds crank up offshore. Therefore, we extended the WARNING for hazardous seas inside 10nm north of the Cape through Thursday night. Seas should diminish slightly on Friday, however it will still be steep and hazardous both on Friday and Saturday. Steep and uncomfortable seas will most likely continue on Sunday especially from Cape Mendocino northward. && .EKA WATCHES/WARNINGS/ADVISORIES... CA...NONE. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 5 PM PDT this afternoon FOR PZZ450. Hazardous Seas Warning until 5 AM PDT Friday FOR PZZ450. Gale Warning until 9 PM PDT Saturday FOR PZZ470. Small Craft Advisory until 9 PM PDT Saturday FOR PZZ455. Gale Warning until 9 PM PDT Saturday FOR PZZ475. && $$ Visit us at http://WWW.WEATHER.GOV/EUREKA Follow us on facebook and twitter at: http://www.facebook.com/NWSEureka http://www.twitter.com/nwseureka FOR FORECAST ZONE INFORMATION SEE FORECAST ZONE MAP ONLINE: http://www.weather.gov/eureka/zonemap.png
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
AREA FORECAST DISCUSSION
National Weather Service San Diego CA
136 PM PDT TUE JUN 28 2016 .SYNOPSIS... High pressure aloft will continue hot weather inland through Wednesday...followed by slow cooling into Saturday as high pressure aloft weakens and a weak low pressure trough develops along the coast. A disturbance, in addition to moisture aloft and weak instability, will continue to produce a slight chance for showers and thunderstorms over the mountains, high deserts, and Coachella valley through early evening. Residual moisture will produce a slight chance of afternoon and early evening mountain and high desert thunderstorms Wednesday. Main threats from thunderstorms are dry lightning and gusty winds. The marine layer and onshore flow will keep coastal high temperatures lower with areas of night and morning low clouds and fog. Another warm-up may begin on Sunday. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Water vapor satellite currently indicates an upper level wave slowly drifting north over San Bernardino county, with a ridge over the four corners area. Currently, radar indicates some thunderstorms over the San Gorgonio Wilderness/Big Bear area, and some sprinkles over the High Deserts. Meanwhile, visible satellite shows that marine layer stratus has cleared out of inland areas, but is sticking to the coast due to the strong 13 deg C inversion shown by the 12Z Miramar sounding. The sounding also shows significant drying, with the precipitable water having dropped to 0.86 inches, compared to 1.48 inches yesterday. The wave will lift north through the day today. Latest SPC mesoanalysis shows an area of 500 J/KG of MUCAPE over the mountains, and NAM12 shows this amount of instability continuing through early evening. Thus, hi-res models and the HRRR focus any shower/thunderstorm activity over those areas, as well as the High Deserts. Meanwhile, with the strong ridge over the region today, it is hot once again in the valleys, mountains and deserts. Temperatures have risen to the low 110s in the lower deserts, low 100s in the Inland Empire, mid to high 90s in the lower mountain slopes, and low to mid 90s in the San Diego county valleys. However, warming has been slower in the High Deserts due to the higher amount of cloud cover in that area. Expect highs to rise to 5-10 degrees, and locally 15 degrees, above normal today. Meanwhile, local WRF shows the marine layer remaining at a similar depth tonight, if not slightly deeper, with stratus/fog moving into the coast and western valleys. Precipitable water stays down around 0.8 inches on Wednesday, but there may be enough residual moisture to produce isolated thunderstorms over the mountains during the afternoon and early evening. The ridge stays similarly strong over our region on Wednesday, so the hot conditions will continue for inland areas. The Heat Advisory remains in effect for the Inland Empire, mountains and deserts through 8 PM Wednesday. Southwest flow aloft will produce further drying on Thursday, so any thunderstorm activity that day is unlikely. The ridge also starts to weaken on Thursday as a trough moves in over the West coast, so it should start to cool a bit with also some deepening of the marine layer. Cooling and a deeper marine layer likely to continue Friday and Saturday due to the trough. Models are showing that the flow aloft on Friday turns more southerly, as opposed to southwesterly, and this may allow enough moisture to squeeze into the region for possible afternoon thunderstorms/showers over the mountains. We may start to heat up again Sunday into early next week, as the GFS shows the ridge rebuilding over the region. However, the ECMWF keeps us cooler with a trough along the west coast. && .AVIATION... 281945Z...Coast/Valleys...BKN-OVC low clouds based 700-1000 feet MSL with tops to near 1200 feet MSL over the coastal waters and at most beaches otherwise mostly clear. Stratus will push inland over coastal airports this evening around 29/06z with little change in heights. Risk of low clouds returning as a solid deck this evening is moderate-high so confidence in the KSAN TAF timing is also moderate-high. Local visibilities at or below 3 miles in fog and haze inland edge of the low clouds is expected around 10-15 miles inland. Isolated SHRA/TSRA mainly near the mountains through 29/00z this afternoon with CB bases near 9000 ft MSL and tops to near 35000 ft MSL along with local surface gusts to near 30 knots. Mountains and Deserts...Isolated showers with bases mostly above 10000 ft MSL and little impact on VIS will occur over San Bernardino County and the San Jacinto Mountains with tops to 35000 ft MSL and local surface gusts over 30 knots. Otherwise, SCT-BKN clouds today at/above 10000 ft MSL will dissipate tonight with unrestricted VIS. && .MARINE... 130 pm...No hazardous marine weather is expected through Saturday. && .BEACHES... 130 pm...Long period southerly swells will increase again late Wednesday into Thursday, with the predominant swell 4 feet/17 seconds/200 degrees. This will bring 4-6 foot surf to southwest facing beaches late Wednesday through Friday along with dangerous rip currents. && .FIRE WEATHER... An upper level disturbance will continue to produce a slight chance of dry lightning over Southwest San Bernardino county, the Riverside county mountains and deserts, and the northern San Diego county mountains through early this evening. Enough residual mid- level moisture may be around for some isolated thunderstorm and dry lightning activity Wednesday afternoon and evening over the mountains and high deserts. Thunderstorms will also produce gusty and erratic downdraft winds. Thunderstorms are unlikely Thursday, but there are some indications that there could be some activity on Friday. && .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
925 AM PDT TUE JUN 28 2016 .SYNOPSIS... High pressure aloft will continue hot weather inland through Wednesday...followed by slow cooling into next weekend as high pressure aloft weakens and a weak low pressure trough develops along the coast. A disturbance, in addition to moisture aloft and weak instability, will continue to produce a slight chance for showers and thunderstorms over the mountains, high deserts, and Coachella valley through early evening. Residual moisture will produce a slight chance of afternoon and early evening mountain thunderstorms Wednesday. Main threats from thunderstorms are dry lightning and gusty winds. 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... Water vapor satellite currently indicates an upper level wave slowly drifting north over San Bernardino county, with a ridge over the four corners area. A lightning strike occurred near Daggett earlier, and then over the past couple hours some thunderstorms producing numerous lightning strikes developed over the Coachella Valley. Otherwise, some sprinkles are occurring over Southerwestern San Bernardino county mountains. Meanwhile, visible satellite shows marine layer stratus over the coastal waters and coastal areas, with some stratus/fog making it into the western valleys. The 12Z Miramar sounding shows a strong marine layer inversion of 13 deg C at 1000 ft msl, which means that the stratus will likely have a difficult time of clearing at the immediate coast today. The sounding also shows significant drying, with the precipitable water having dropped to 0.86 inches, compared to 1.48 inches yesterday. The wave will lift north through the day today. The NAM12 shows instability decreasing later in the morning, but then increasing again in the afternoon over the mountain peaks of San Bernardino and Riverside county, with MUCAPE in the 700-300 mb layer reaching near 400 J/KG. Thus, hi-res models and the HRRR focus any shower/thunderstorm activity over those areas, as well as the High Deserts. Given the early morning thunderstorm activity in the Coachella Valley, have updated the forecast to include thunderstorms for that area and also the Inland Empire this morning and this afternoon, and also northern portions of the San Diego county mountains for this afternoon. Meanwhile, with the strong ridge over the region today, it will be hot once again in the valleys, mountains and deserts, while the marine layer keeps it relatively cooler at the coast. Expect highs to rise to 5-10 degrees, and locally 15 degrees, above normal today. Mid 60s dewpoints in the valleys will also make it feel muggy and uncomfortable. However, with the cloud cover this morning over San Bernardino county and Riverside county, those areas may stay a bit cooler than expected. Local WRF shows the marine layer remaining at a similar depth tonight, if not slightly deeper, with stratus/fog moving into the coast and western valleys. Precipitable water stays down around 0.8 inches on Wednesday, but there may be enough residual moisture to produce isolated thunderstorms over the mountains during the afternoon and early evening. The ridge stays similarly strong over our region on Wednesday, so the hot conditions will continue for inland areas. The Heat Advisory remains in effect for the Inland Empire, mountains and deserts through 8 PM Wednesday. Southwest flow aloft will produce further drying on Thursday, so any thunderstorm activity that day is unlikely. The ridge also starts to weaken on Thursday as a trough moves in over the West coast, so it should start to cool a bit and also some deepening of the marine layer is likely. Cooling and a deeper marine layer likely to continue Friday and Saturday due to the trough. We may start to heat up again Sunday into early next week, as the GFS shows the ridge rebuilding over the region. However, the ECMWF keeps us cooler with a trough along the west coast. && .AVIATION... 281610Z...Coast/Valleys...BKN-OVC low clouds based 700-1000 feet MSL with tops to near 1200 feet MSL over the coastal waters and at most beaches otherwise mostly clear. Stratus will redevelop over coastal airports this evening around 29/06z with little change in heights. Risk of low clouds returning as a solid deck this evening is moderate-high so confidence in the KSAN TAF timing is also moderate-high. Local visibilities at or below 3 miles in fog and haze inland edge of the low clouds is expected. Isolated SHRA/TSRA mainly near the mountains through 29/00z this afternoon with CB bases near 9000 ft MSL and tops to near 35000 ft MSL along with local surface gusts to near 30 knots. Mountains and Deserts...Isolated showers with bases mostly above 10000 ft MSL and little impact on VIS will occur over San Bernardino County and the San Jacinto Mountains with bases 9000 ft MSL and tops to 35000 ft MSL and local surface gusts over 30 knots. Otherwise, SCT-BKN clouds today at/above 10000 ft MSL will dissipate tonight with unrestricted VIS. && .MARINE... 930 am...No hazardous marine weather is expected through Saturday. && .BEACHES... 930 am...Long period southerly swells will increase again late today into Thursday, with the predominant swell 4 feet/17 seconds/200 degrees. This will bring 4-6 foot surf to southwest facing beaches late Wednesday through Friday along with dangerous rip currents. && .FIRE WEATHER... An upper level disturbance will continue to produce a slight chance of dry lightning over Southwest San Bernardino county, the Riverside county mountains and deserts, and the northern San Diego county mountains through early this evening. Enough residual mid- level moisture may be around for some isolated thunderstorm and dry lightning activity Wednesday afternoon and evening over the mountains. Thunderstorms will also produce gusty and erratic downdraft winds. The thunderstorm threat should end after Wednesday. && .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 Topeka KS
615 PM CDT WED JUN 29 2016 ...Update to aviation forecast discussion... .SHORT TERM...(This Evening through Thursday) Issued at 301 PM CDT WED JUN 29 2016 Current WV imagery at 20Z suggests a remnant MCV continues to slowly drift east across northeastern KS just south of the Nebraska border. MLCAPE values have reached 2500-3000 J/kg per meso analysis and with an upper level shortwave crossing the area, 0-6km shear values are around 30kts. This has provided enough support for at least a couple stronger clusters of thunderstorms over the area. All this activity is slowly moving east and should exit the area by around 5- 6pm this evening. Another shortwave moving through northwest flow aloft should arrive early Thursday morning as it is currently over western portions of the Northern Plains. Although this is not a slam dunk forecast, there are some indications that as the aforementioned shortwave may make its way into the area and provide additional support for some nocturnal storms expected to develop over western IA into far eastern NE and move into eastern portions of the forecast area late tonight after midnight. Additional complex currently developing over western South Dakota may have enough support via an axis of instability setting up into central Kansas as the LLJ veers overnight. These two areas may end up merging in the early morning hours on Thursday and provide a focus for morning storms mainly south of I-70. Depending on how any outflows set up and linger throughout the day will determine where afternoon convection will once again enter the forecast. Expecting this activity will be off over the southern portions of the forecast area as of now. Due to the low confidence in the activity developing and moving in from Western IA, have gone with slight chance POPs overnight and any expected severe activity would likely be in the form of some stronger wind gusts and hail. Temps once again will depend on remnant cloud cover, but expecting high temps tomorrow to reach into the mid 80s. Overnight temps tonight should only dip into the upper 60s and lower 70s with no significant airmass changes but locally impacted by any overnight cold pools. .LONG TERM...(Thursday Night through Wednesday) Issued at 301 PM CDT WED JUN 29 2016 Thunderstorms expected to fire again Thursday afternoon and evening across northwest KS and southwest NE and propagate southeastward in northwest flow aloft. Given source region of expected development, would expect southwest portion of forecast area to have the best chance for overnight precipitation, with lesser possibilities in far northeast KS. Redevelopment north of boundary in warm advection pattern should occur on Friday afternoon with once again best chances across southwest forecast area. As boundary lifts to the north Friday night associated with development of surface low near the CO/OK border, more organized convective complex is expected. Dewpoints in the upper 60s to around 70, PWs between 1.5 and 2 inches and continued positive theta-e advection up over boundary could lead to a round of heavy precipitation, that could continue into Saturday morning in the northeast. Boundary hangs around in central or southern KS Saturday afternoon, depending on which model you look at. Redevelopment of thunderstorms Saturday afternoon seems likely, but location of that development, and best chances hard to pin down this far in advance. Boundary remains in the area Saturday night into Sunday evening with a relatively well-defined shortwave trough moving across the Central Plains in nearly zonal flow aloft. Thus, thunderstorm chances continue through at least Sunday evening, with locally heavy rainfall in some areas. Flooding chances will have to be watched with several periods of thunderstorms over the weekend. After Sunday evening, smaller chances for isolated thunderstorms exist through early next week. Temperatures from Friday through Sunday will be mild for this time of year with plenty of cloud cover and areas of precipitation, with highs only in the upper 70s to lower 80s expected. From Monday through Wednesday of next week, temperatures should warm and heights rise aloft and more sunshine is expected. && .AVIATION...(For the 00Z TAFS through 00Z Thursday Evening) Issued at 614 PM CDT WED JUN 29 2016 Overall, VFR conditions are expected along with light and variable winds. There is a slight chance for a complex of storms to make its way into the area from the northwest mainly after 11Z tomorrow morning. Have left this mention out of the TAFs for now until confidence is higher. && .TOP Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Drake LONG TERM...GDP AVIATION...Heller
  [top] Area Forecast Discussion National Weather Service Goodland KS 514 PM MDT WED JUN 29 2016 .SHORT TERM...(This evening through Thursday) Issued at 157 PM MDT Wed Jun 29 2016 As of 3 PM CDT/2 PM MDT, skies across the Tri-State Region are mostly clear. A few cumulus clouds have recently developed over east Colorado and extreme northwest Kansas. Temperatures are in the mid to upper 80s for most locations. Winds are generally less than 10 mph for most locations. However, south winds are beginning to pick up to 10-15 mph, gusting to 20 mph. At the surface, an area of low pressure was located along the Colorado Front Range. A weak front/remnant outflow boundary is located across eastern Colorado. Aloft, a shortwave trough is moving across Colorado. Thunderstorms have developed over the Rockies ahead of this trough. For this evening and tonight, am expecting another round of strong to severe thunderstorms to move across the region. High resolution guidance, while varying somewhat amongst each piece of guidance, suggest that storms develop this afternoon over eastern Colorado and Wyoming. Then, as the evening progresses, storms should coalesce into another complex or two, spreading southeast across the Tri- State Region. Storms should exit the region after midnight. Overall, am not anticipating quite the storm intensity as last night as the atmosphere has been worked over some. Current mesoanalysis does indicate SBCAPE up to 2500 J/KG in some locations but a cap persists. When the cap breaks, strong/severe thunderstorms should quickly develop. In addition, strong shear remains (0-6 KM Bulk Shear is 40-50 kts). Therefore, anticipating the primary threat with these storms to be damaging winds once again. Any initial development will be capable of large hail, very large possible. Further, recent heavy rains have saturated the soils for some locations. These locations, if they receive additional heavy rain from thunderstorms, would be prone to flash flooding tonight. Was not confident enough to issue a flash flood watch at this time due to some disagreement in guidance with regards to the movement of this complex. For tomorrow, a cold front should push south across the region. As a result of the front and likely extensive cloud cover, cooler temperatures are forecast. Instability parameters remain favorable for some strong/severe thunderstorms, particularly later in the afternoon hours. Thinking the highest chances for thunderstorms (in the afternoon) will be along/west of a line from Benkelman, Nebraska to Tribune, Kansas. Large hail and damaging winds will be possible. Winds aloft should weaken so slower storm movement appears likely. In addition, precipitable water content increases. Therefore, heavy rain and flash flooding may become an issue. .LONG TERM...(Thursday night through Wednesday) Issued at 303 PM MDT Wed Jun 29 2016 Forecast issues will continue to be the threat of thunderstorms, severe weather, and heavy rainfall...especially into the beginning of the weekend. Satellite showing showing an amplified pattern from the eastern Pacific into North America. Upper ridge is currently near the four corners region with subtropical working its way around western side of this ridge. At mid levels...The Canadian/Gfs/Ecmwf were doing the best with the Nam and Sref starting out the worst. The Canadian and gfs did the best on the low level thermal field. Thursday night...numerous shortwave troughs shown. Models appear to not show a lot of lift until the later half of the night when a stronger and negatively tilted shortwave trough approaches the area. Initially most of the precipitation looks to be in the southwest half with a gradual increase in the last half of the night. Some severe possible with probably a greater threat for heavy rainfall due to above normal Pwats. Friday/Friday night...Negatively tilted mid/upper level trough will move slowly toward the area during the day with two different shortwave troughs moving through. One will be early and is the one that begins to affect the area late Thursday night and will move northeast through the day. A second shortwave trough moves in from the southwest in the afternoon. The lift is actually the strongest during the night, with the highest pops of this period, as the entire upper trough moves in closer to the area. Right rear quadrant of jet moves across during the afternoon and evening. There may be a brief break somewhere in their during the day however that will be hard to time. Will have high chance to likely pops in during the day and likely during the night. It may be more embedded thunderstorms in the showers in the morning with more instability and thunderstorms present in the afternoon and night. With a cooler air mass and lots of cloud cover, instability will not be very high. Could not rule out an isolated severe storm but do not expect widespread severe weather. The main threat will be heavy rainfall. Pwats remain near or a little above 1.5 through the entire period which is near 2 standard deviations above normal. Storm motions increase through the day but heavy rainfall still appears to be another good bet. Looks like temperatures will have a hard time climbing this day with cloud cover, ongoing rainfall, and low level upslope. Saturday...the day starts with a complex mid level trough over the forecast area. It appears it slowly moves across the area and then stalls/deepens on top of our area as another shortwave trough comes down the west side of the trough. The models appear to start to try to close off a circulation at 700 mb. Also it appears that a front is near to just southeast of the area. Pwats actually increase into the 1.5 to 2 inch range. It appears that heavy rainfall will be the main threat. However, with a mid level center parked over the area, it could set the stage for low top supercells and landspouts. Saturday night through Wednesday...Continued active period looks to continue. In general the models are the same with the mid level ridge getting suppressed much further south and weak troughing along the west coast of North America. Numerous shortwave troughs are embedded within this flow as one would expect the models are having trouble handling them and do differ on the details of speed and amplitude. Models/Wpc manual progs show synoptic boundaries in and near the area through the whole period. However, given the flow pattern and shortwave troughs aloft, models will probably handle these well at this distance. And that is not even accounting for the mesoscale affects of repeated bouts of thunderstorms. The extended blend provided higher pops on saturday night then steadily decreases pops and has only spotty slight chance to low chance pops for the rest of the period. This looks reasonable considering the model differences and uncertainties in such a complex pattern. However, definitely will be possible for pops to end up being higher. Warmer trend looks to be store, and also appears to be reasonable. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 507 PM MDT Wed Jun 29 2016 VFR conditions expected for the TAFs. Another round of strong to severe storms will impact the TAF sites tonight. Main threat with these storms will be damaging winds, however large hail is possible with these storms along with heavy rainfall. KGLD will be impacted first followed by KMCK. The storm activity will be south of the sites not long after 6z, possibly sooner if the storms move faster than expected. && .GLD Watches/Warnings/Advisories... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...RRH LONG TERM...BULLER AVIATION...JTL
Area Forecast Discussion National Weather Service Dodge City KS 600 PM CDT WED JUN 29 2016 ...Updated Aviation... .SHORT TERM...(This evening through Thursday) Issued at 251 PM CDT Wed Jun 29 2016 A wind shift line has moved to between Garden City and Dodge City this afternoon with some cumulus just south of Dodge City, and another area of more enhanced cumulus in parts of Barber County. Forecast soundings are unstable with only a weak cap over the Dodge City area and 2000 to 3000 J/kg forecast CAPE. There could be an isolated thunderstorm near the wind shift line and then a slightly better chance in the Barber County area. If any storm develops it could go briefly severe with quarter hail and a strong wind gust. Then later tonight, models show the best chances for rainfall are mainly north of Dodge City, however with this current northwest flow pattern, any storms that develop in eastern Colorado and Nebraska could dive southward into much of the area. Will keep 30 to 50 percent chance going. Severe storms do not look likely with the main threat of strong outflow winds, small hail, and heavy rainfall with any storm complex that can develop. It may also be more difficult for storms to form in far western Kansas this evening and overnight as 700 mb temps are fairly warm around 15C. Lows tonight will range from the mid to upper 60s with light southeast winds. For Thursday, a stronger shortwave in northwest flow aloft is forecast for the afternoon and evening with an attendant cold front moving across western Kansas. Will keep fairly high chances for rainfall going, again with a potential of heavy rainfall. Could also have a chance of strong to severe storms with stronger wind shear forecast. .LONG TERM...(Thursday night through Wednesday) Issued at 305 PM CDT Wed Jun 29 2016 For the period of Thursday night into next Wednesday, an ongoing convective complex of storms may be moving across parts of western Kansas Thursday night with aggravated northwest flow aloft. For Friday northwest flow aloft begins to transition to more zonal flow with more shortwaves forecast into Sunday across the Western High Plains. Will keep fairly high chances going for rainfall, and areas of heavy rainfall still look good. After Sunday, rainfall chances decrease as the main upper jet and any shortwaves move north. Highs will be cooler and in the 80s into Sunday, but then warm back into the 90s by mid week next week. Lows will be mainly in the 60s then warm to around 70 after Monday. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 600 PM CDT Wed Jun 29 2016 NW flow aloft expected to spread more SHRA/TSRA into SW Kansas again late tonight. HRRR model solution indicates thunderstorm complex over NE Colorado at 23z will move rapidly SE and begin affecting the terminals around midnight. HRRR solution performed well with last night`s convection, so used it again as a first approximation to place convective TEMPO groups in the 00z TAFs. Strong outflow winds to 50 kts will again be the primary concern, with HRRR suggesting impacts to aviation are most likely at GCK. Stronger shortwave in the NW flow arrives Thursday, with NAM model suggesting potentially widespread TSRA after 18z Thursday. Only included VCTS/CB for now, but TEMPOs are likely with future TAF packages for Thursday. && .PRELIMINARY POINT TEMPS/POPS... DDC 68 89 65 82 / 30 50 60 50 GCK 67 88 65 83 / 40 50 60 50 EHA 67 91 64 86 / 30 50 60 50 LBL 68 92 66 87 / 30 50 60 50 HYS 66 85 64 81 / 40 40 40 50 P28 69 91 68 84 / 30 50 60 50 && .DDC Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Kruse LONG TERM...Kruse AVIATION...Turner
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
1214 PM CDT TUE JUN 28 2016 ...Update to aviation forecast discussion... .SHORT TERM...(Today and Tonight) Issued at 411 AM CDT TUE JUN 28 2016 A complex of thunderstorms continued to move southeast early this morning, showing signs of intermittent severe downburst winds. Overall parameters are not particularly favorable for severe storms, but the organized cold pool has been able to interact with elevated instability and modest deep layer wind shear to provide periods of intensification and organization of rear inflow jets and downdraft surges. It is these features that will continue to be monitored for severe wind potential...and severe hail is a minimal secondary hazard along with locally heavy rain. These storms have become organized enough that they seem to be developing a convectively enhanced MCV aloft, and would expect this feature to move southeast with the storms and probably continue to enhance convection and rainfall rates...and also steer the motion of the storms a bit. Expect storms to gradually diminish and move out of the area by mid to late morning. Beyond that time, should see mainly dry conditions through the rest of the day. Additional storms will likely develop in Nebraska and move south and southeast into the evening but there is some uncertainty in whether they will have sufficient instability to progress into northeast KS, and chances seem pretty low. A more organized MCS is likely to develop farther west, and remain mainly west of the forecast area through the evening although the eastern fringes could stretch into north central KS. Then later on tonight, additional forcing moves across eastern Nebraska...and again may be able to support storms into central and eastern KS closer to sunrise but instability should be weak and severe potential seems quite low or nil from noon today at least through tonight. .LONG TERM...(Wednesday through Monday) Issued at 411 AM CDT TUE JUN 28 2016 Overall extended period remains unsettled with an active pattern of weak embedded troughs traversing through the region, bringing multiple chances for convection through Sunday. There are a few periods where confidence in precip increases with a more optimal forcing mechanism Thursday evening through Saturday evening. Otherwise, confidence is fairly low in coverage of pops - highly dependent on mesoscale factors that mid term models are unable to discern this far out. Convection on Wednesday afternoon and evening, mainly focuses over north central areas. Timing of convection on Tuesday evening will dictate this scenario as the NAM continues to be highlighting an MCS over western KS during this time, while other guidance focuses the activity further east towards central/north central areas during the early afternoon Wednesday. Will need to monitor highs as guidance may be trending too cool based on the coverage of precipitation and cloud cover. I raised highs a few degrees for now as current thinking sides with precip remaining mostly west of our area with mostly sunny skies in the late afternoon and temps in the middle 80s. Will likely see a break Wednesday evening before the cold front arrives from the west Thursday afternoon, providing a better source of lift for thunderstorms to develop. Lapse rates aloft remain weak while ample instability and effective shear values peak at around 40 kts, lending to a few strong to severe storms, especially along and south of the Interstate 70 corridor. Raised pops to likely south of Interstate 70 for this period as all guidance points to the boundary hanging up across southern KS with periods of thunderstorms redeveloping in the afternoon hours on Friday. Mid level flow becomes more westerly by this time, allowing for several vorticity lobes to track from the southwest through Saturday evening. Organized severe weather during this period is low, but cannot rule out isolated storms being on the stronger side. On the north side of the front, much of northeast Kansas remains on the cool side with highs in the lower 80s and lows in the 60s. On Sunday and Monday, while models are in large disagreement, there are trends in shortwave ridging aloft bring a temporary end to precip chances for the July fourth holiday. During the day, southerly flow returns along with the heat and humidity as readings rise in to the lower 90s. && .AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon) Issued at 1211 PM CDT TUE JUN 28 2016 VFR conditions are expected throughout the period. Winds will decrease below 10 knots near dusk this evening. Thunderstorms will be possible near dawn tomorrow morning as a complex of storms moves south out of Nebraska. However, current thinking is storms will stay west of the terminals. Future outlooks will continue to analyze the potential. && .TOP Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Barjenbruch LONG TERM...Prieto AVIATION...Baerg
Area Forecast Discussion National Weather Service Dodge City KS 1201 PM CDT TUE JUN 28 2016 ...Updated for Aviation... .SHORT TERM...(Today and tonight) Issued at 325 AM CDT Tue Jun 28 2016 The northwest flow pattern is underway, and along with it a challenging forecast. At the time of this writing at 0800 UTC, there were two small MCSs, one across far eastern Colorado and adjacent far western KS with a second one across far north central KS. It looks like a majority of the southwest KS region will avoid both of these MCSs as they track almost due south. The exception will be the western six counties were some rainfall of around a quarter inch can be expected with some locally higher amounts through the mid-morning hours before the MCS weakens. Some of the hourly HRRR runs want to merge the two MCSs, so that will have to be watched later in the morning, but right now that doesn`t seem to be happening, so we will be keeping POPs fairly low with the exception of far southwest and west central KS. It is unclear exactly how convection will evolve late this afternoon through tonight. We could see a repeat of yesterday, except starting off a bit farther north in Nebraska. A mature MCS never really materialized last night like was forecast, however that does not mean that one large, coherent, long-lived MCS won`t happen tonight. Signals are certainly there in both the high resolution convective allowing models and lower resolution models. The NAM12 is particularly bullish, showing a significant QPF signal rolling SSE from western Nebraska into southwest KS by 12z Wednesday. Both the NCEP WRF-ARW and WRF-NMMB show something coherent rolling across the same generally area before decaying around or shortly after 09z Wednesday. In the official forecast, we will have 40-50 POPs going mainly east and north of a Dighton-Dodge-Greensburg- Pratt line with greatest confidence and QPF forecast values up along the I-70 corridor. .LONG TERM...(Wednesday through Monday) Issued at 325 AM CDT Tue Jun 28 2016 The active northwest flow pattern will continue through the end of the week. A couple of things that will probably act to enhance precipitation coverage and intensity later in the week will be 1) a fairly decent surface front which will slow down and perhaps become quasi-stationary across southern Kansas and 2) some minor mid level perturbations/enhanced mid level moisture rotating around weak ridging, thanks to abundance of mountain convection across the southern Rockies. POPs in the Long Term will be highest Thursday Night through Saturday Night with 12-hr POPs every period in the 40- 60 percent territory somewhere across our forecast area from west central KS through south central KS. It still looks as though some areas will see potentially excessive rainfall once the polar front gets down here, given all the moisture that will be around and the generally weak mid-upper level flow leading to slow-moving convection. && .AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon) Issued at 1156 AM CDT Tue Jun 28 2016 Light east to southeasterly upslope will prevail with VFR conditions. A complex of thunderstorms is then forecast to drop south to southeastward across much of south central Kansas late tonight and towards morning. The best guess for timing is at KHYS around 08-11Z and 09-12z at KGCK and KDDC. Strong outflow winds will be the main threat along with heavy rainfall and frequent lightning. && .PRELIMINARY POINT TEMPS/POPS... DDC 88 67 90 66 / 20 40 20 30 GCK 89 66 91 66 / 20 30 20 20 EHA 90 67 94 66 / 40 20 20 30 LBL 91 67 94 67 / 30 20 20 30 HYS 87 66 86 65 / 20 50 40 40 P28 91 68 90 69 / 20 30 30 40 && .DDC Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Umscheid LONG TERM...Umscheid AVIATION...Kruse
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
647 AM CDT TUE JUN 28 2016 ...Update to aviation forecast discussion... .SHORT TERM...(Today and Tonight) Issued at 411 AM CDT TUE JUN 28 2016 A complex of thunderstorms continued to move southeast early this morning, showing signs of intermittent severe downburst winds. Overall parameters are not particularly favorable for severe storms, but the organized cold pool has been able to interact with elevated instability and modest deep layer wind shear to provide periods of intensification and organization of rear inflow jets and downdraft surges. It is these features that will continue to be monitored for severe wind potential...and severe hail is a minimal secondary hazard along with locally heavy rain. These storms have become organized enough that they seem to be developing a convectively enhanced MCV aloft, and would expect this feature to move southeast with the storms and probably continue to enhance convection and rainfall rates...and also steer the motion of the storms a bit. Expect storms to gradually diminish and move out of the area by mid to late morning. Beyond that time, should see mainly dry conditions through the rest of the day. Additional storms will likely develop in Nebraska and move south and southeast into the evening but there is some uncertainty in whether they will have sufficient instability to progress into northeast KS, and chances seem pretty low. A more organized MCS is likely to develop farther west, and remain mainly west of the forecast area through the evening although the eastern fringes could stretch into north central KS. Then later on tonight, additional forcing moves across eastern Nebraska...and again may be able to support storms into central and eastern KS closer to sunrise but instability should be weak and severe potential seems quite low or nil from noon today at least through tonight. .LONG TERM...(Wednesday through Monday) Issued at 411 AM CDT TUE JUN 28 2016 Overall extended period remains unsettled with an active pattern of weak embedded troughs traversing through the region, bringing multiple chances for convection through Sunday. There are a few periods where confidence in precip increases with a more optimal forcing mechanism Thursday evening through Saturday evening. Otherwise, confidence is fairly low in coverage of pops - highly dependent on mesoscale factors that mid term models are unable to discern this far out. Convection on Wednesday afternoon and evening, mainly focuses over north central areas. Timing of convection on Tuesday evening will dictate this scenario as the NAM continues to be highlighting an MCS over western KS during this time, while other guidance focuses the activity further east towards central/north central areas during the early afternoon Wednesday. Will need to monitor highs as guidance may be trending too cool based on the coverage of precipitation and cloud cover. I raised highs a few degrees for now as current thinking sides with precip remaining mostly west of our area with mostly sunny skies in the late afternoon and temps in the middle 80s. Will likely see a break Wednesday evening before the cold front arrives from the west Thursday afternoon, providing a better source of lift for thunderstorms to develop. Lapse rates aloft remain weak while ample instability and effective shear values peak at around 40 kts, lending to a few strong to severe storms, especially along and south of the Interstate 70 corridor. Raised pops to likely south of Interstate 70 for this period as all guidance points to the boundary hanging up across southern KS with periods of thunderstorms redeveloping in the afternoon hours on Friday. Mid level flow becomes more westerly by this time, allowing for several vorticity lobes to track from the southwest through Saturday evening. Organized severe weather during this period is low, but cannot rule out isolated storms being on the stronger side. On the north side of the front, much of northeast Kansas remains on the cool side with highs in the lower 80s and lows in the 60s. On Sunday and Monday, while models are in large disagreement, there are trends in shortwave ridging aloft bring a temporary end to precip chances for the July fourth holiday. During the day, southerly flow returns along with the heat and humidity as readings rise in to the lower 90s. && .AVIATION...(For the 12Z TAFS through 12Z Wednesday Morning) Issued at 645 AM CDT TUE JUN 28 2016 Area of rain and thunderstorms will impact TAF sites through around 14Z before coming to an end. Will have periods of reduced vis and increased wind speeds with these storms. Thunderstorms will probably be done after 14Z through the remainder of the TAF period, but with lower end confidence. && .TOP Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Barjenbruch LONG TERM...Prieto AVIATION...Barjenbruch
Area Forecast Discussion National Weather Service Wichita KS 625 AM CDT TUE JUN 28 2016 .SYNOPSIS... Issued at 228 AM CDT Tue Jun 28 2016 In the upper levels, ridging is centered over the four corners region with a shortwave diving southeast over the western Great Lakes. At the surface, high pressure is situated over ND/northern MN with a loose cold front stretching across northern MO into northern KS. && .SHORT TERM...(Today through Friday night) Issued at 228 AM CDT Tue Jun 28 2016 Just like last night, have low confidence in what is forcing convection over northern KS as elevated parcels remain uncapped. Best guess is that a weak upper impulse, convectively induced or not, is what sparked off storms over far northern KS/southern Nebraska. Will continue to monitor trends too see if this small complex holds together, as we may need to increase pops over central KS this morning. Outside of this morning activity, should see a setup fairly similar to what played out Mon, with the high Plains of KS/Nebraska seeing the bulk of the daytime convection. These storms should track southeast overnight and possibly a bit further east compared to Mon evenings storms due to the better moisture transport being pushed slightly east. Will keep with the overall theme of keeping the highest storm chances along and especially west of I-135. Feel that best the chance for storms Wed looks to be Wed morning as the overnight storms continue to push southeast. Northwest flow will remain over the Plains for Wed through Thu night. There is a good signal that another round of elevated convection will develop Wed night in an area of strong isentropic lift in the 310-315k layer. 700mb temps also show a fairly tight gradient through the forecast area with some warm advection over this baroclinic zone. For Thu into Thu night, there is good model agreement in a cold front sliding down into the central Plains with this feature stretching from northern MO into SW KS by 00z Fri. At the same time, models also agree on some upper energy lifting out of the desert sw and across the area for Fri into Fri night. The combination of the front and a series of weak impulses will keep decent storm chances in for Thu night through Fri night with the southern half of KS looking to have the better chances. Temps will finally start to cool to closer to or just below seasonal normals. Most of the area should see 80s for highs for Thu with much cooler air moving down across the region for Fri. .LONG TERM...(Saturday through Monday) Issued at 228 AM CDT Tue Jun 28 2016 Will keep fairly high storm chances in for Sat as the zonal pattern remains active with models showing additional pieces of energy lifting out of the four corners region. In addition, the weak surface boundary looks to remain over the area through Sun morning. There looks to be some agreement in the medium range models in some weak upper ridging over the central/southern Plains for Sun night into Mon, which should push the better precip chances east. && .AVIATION...(For the 12Z TAFS through 12Z Wednesday morning) Issued at 618 AM CDT Tue Jun 28 2016 Main aviation concern will be storms this morning and again later tonight. Storms developed over extreme north central KS a few hours ago. Tough to find the forcing for these storms but best guess is that this activity is developing ahead of a weak upper impulse diving southeast in the NW flow. Current thinking is that this activity will continue for at least the next few hours. Will include either a tempo group or vcts at all sites this morning with the exception of KICT. Late afternoon storms are expected to develop once again over western Nebraska with this activity diving southeast overnight. Areas generally west of I-135 will have the best chance to see overnight storms, so will run with VCTS after 03z at KRSl-KGBD-KSLN. There has been some periodic fog at KCNU early this morning but with sun coming up and storms approaching, not expecting this to last much longer. Lawson && .PRELIMINARY POINT TEMPS/POPS... Wichita-KICT 90 68 86 69 / 20 20 20 40 Hutchinson 88 67 87 67 / 20 30 30 40 Newton 89 67 86 67 / 30 20 20 40 ElDorado 89 68 86 67 / 30 20 20 40 Winfield-KWLD 90 69 88 69 / 20 10 20 30 Russell 89 66 85 65 / 40 50 50 50 Great Bend 89 66 86 66 / 30 50 40 40 Salina 90 66 85 67 / 30 40 30 50 McPherson 88 66 86 66 / 30 30 30 40 Coffeyville 90 68 89 69 / 10 10 20 30 Chanute 90 67 87 67 / 30 10 20 40 Iola 89 66 86 67 / 40 10 20 50 Parsons-KPPF 89 68 88 68 / 20 10 20 40 && .ICT Watches/Warnings/Advisories... None. && $$ SHORT TERM...RBL LONG TERM...RBL AVIATION...RBL
Area Forecast Discussion National Weather Service Wichita KS 625 AM CDT TUE JUN 28 2016 .SYNOPSIS... Issued at 228 AM CDT Tue Jun 28 2016 In the upper levels, ridging is centered over the four corners region with a shortwave diving southeast over the western Great Lakes. At the surface, high pressure is situated over ND/northern MN with a loose cold front stretching across northern MO into northern KS. && .SHORT TERM...(Today through Friday night) Issued at 228 AM CDT Tue Jun 28 2016 Just like last night, have low confidence in what is forcing convection over northern KS as elevated parcels remain uncapped. Best guess is that a weak upper impulse, convectively induced or not, is what sparked off storms over far northern KS/southern Nebraska. Will continue to monitor trends too see if this small complex holds together, as we may need to increase pops over central KS this morning. Outside of this morning activity, should see a setup fairly similar to what played out Mon, with the high Plains of KS/Nebraska seeing the bulk of the daytime convection. These storms should track southeast overnight and possibly a bit further east compared to Mon evenings storms due to the better moisture transport being pushed slightly east. Will keep with the overall theme of keeping the highest storm chances along and especially west of I-135. Feel that best the chance for storms Wed looks to be Wed morning as the overnight storms continue to push southeast. Northwest flow will remain over the Plains for Wed through Thu night. There is a good signal that another round of elevated convection will develop Wed night in an area of strong isentropic lift in the 310-315k layer. 700mb temps also show a fairly tight gradient through the forecast area with some warm advection over this baroclinic zone. For Thu into Thu night, there is good model agreement in a cold front sliding down into the central Plains with this feature stretching from northern MO into SW KS by 00z Fri. At the same time, models also agree on some upper energy lifting out of the desert sw and across the area for Fri into Fri night. The combination of the front and a series of weak impulses will keep decent storm chances in for Thu night through Fri night with the southern half of KS looking to have the better chances. Temps will finally start to cool to closer to or just below seasonal normals. Most of the area should see 80s for highs for Thu with much cooler air moving down across the region for Fri. .LONG TERM...(Saturday through Monday) Issued at 228 AM CDT Tue Jun 28 2016 Will keep fairly high storm chances in for Sat as the zonal pattern remains active with models showing additional pieces of energy lifting out of the four corners region. In addition, the weak surface boundary looks to remain over the area through Sun morning. There looks to be some agreement in the medium range models in some weak upper ridging over the central/southern Plains for Sun night into Mon, which should push the better precip chances east. && .AVIATION...(For the 12Z TAFS through 12Z Wednesday morning) Issued at 618 AM CDT Tue Jun 28 2016 Main aviation concern will be storms this morning and again later tonight. Storms developed over extreme north central KS a few hours ago. Tough to find the forcing for these storms but best guess is that this activity is developing ahead of a weak upper impulse diving southeast in the NW flow. Current thinking is that this activity will continue for at least the next few hours. Will include either a tempo group or vcts at all sites this morning with the exception of KICT. Late afternoon storms are expected to develop once again over western Nebraska with this activity diving southeast overnight. Areas generally west of I-135 will have the best chance to see overnight storms, so will run with VCTS after 03z at KRSl-KGBD-KSLN. There has been some periodic fog at KCNU early this morning but with sun coming up and storms approaching, not expecting this to last much longer. Lawson && .PRELIMINARY POINT TEMPS/POPS... Wichita-KICT 90 68 86 69 / 20 20 20 40 Hutchinson 88 67 87 67 / 20 30 30 40 Newton 89 67 86 67 / 30 20 20 40 ElDorado 89 68 86 67 / 30 20 20 40 Winfield-KWLD 90 69 88 69 / 20 10 20 30 Russell 89 66 85 65 / 40 50 50 50 Great Bend 89 66 86 66 / 30 50 40 40 Salina 90 66 85 67 / 30 40 30 50 McPherson 88 66 86 66 / 30 30 30 40 Coffeyville 90 68 89 69 / 10 10 20 30 Chanute 90 67 87 67 / 30 10 20 40 Iola 89 66 86 67 / 40 10 20 50 Parsons-KPPF 89 68 88 68 / 20 10 20 40 && .ICT Watches/Warnings/Advisories... None. && $$ SHORT TERM...RBL LONG TERM...RBL AVIATION...RBL
Area Forecast Discussion National Weather Service Dodge City KS 604 AM CDT TUE JUN 28 2016 ...UPDATE TO AVIATION... .SHORT TERM...(Today and tonight) Issued at 325 AM CDT Tue Jun 28 2016 The northwest flow pattern is underway, and along with it a challenging forecast. At the time of this writing at 0800 UTC, there were two small MCSs, one across far eastern Colorado and adjacent far western KS with a second one across far north central KS. It looks like a majority of the southwest KS region will avoid both of these MCSs as they track almost due south. The exception will be the western six counties were some rainfall of around a quarter inch can be expected with some locally higher amounts through the mid-morning hours before the MCS weakens. Some of the hourly HRRR runs want to merge the two MCSs, so that will have to be watched later in the morning, but right now that doesn`t seem to be happening, so we will be keeping POPs fairly low with the exception of far southwest and west central KS. It is unclear exactly how convection will evolve late this afternoon through tonight. We could see a repeat of yesterday, except starting off a bit farther north in Nebraska. A mature MCS never really materialized last night like was forecast, however that does not mean that one large, cohernet, long-lived MCS won`t happen tonight. Signals are certainly there in both the high resolution convective allowing models and lower resolution models. The NAM12 is particularly bullish, showing a significant QPF signal rolling SSE from western Nebraska into southwest KS by 12z Wednesday. Both the NCEP WRF-ARW and WRF-NMMB show something coherent rolling across the same generally area before decaying around or shortly after 09z Wednesday. In the official forecast, we will have 40-50 POPs going mainly east and north of a Dighton-Dodge-Greensburg-Pratt line with greatest confidence and QPF forecast values up along the I-70 corridor. .LONG TERM...(Wednesday through Monday) Issued at 325 AM CDT Tue Jun 28 2016 The active northwest flow pattern will continue through the end of the week. A couple of things that will probably act to enhance precipitation coverage and intensity later in the week will be 1) a fairly decent surface front which will slow down and perhaps become quasi-stationary across southern Kansas and 2) some minor mid level perturbations/enhanced mid level moisture rotating around weak ridging, thanks to abundance of mountain convection across the southern Rockies. POPs in the Long Term will be highest Thursday Night through Saturday Night with 12-hr POPs every period in the 40- 60 percent territory somewhere across our forecast area from west central KS through south central KS. It still looks as though some areas will see potentially excessive rainfall once the polar front gets down here, given all the moisture that will be around and the generally weak mid-upper level flow leading to slow-moving convection. && .AVIATION...(For the 12Z TAFS through 12Z Wednesday morning) Issued at 602 AM CDT Tue Jun 28 2016 VFR conditions will prevail at all TAF sites through early this evening. Light and variable winds will turn southeasterly 10 to 20kt this afternoon as a lee side trough of low pressure strengthens across eastern Colorado today. && .PRELIMINARY POINT TEMPS/POPS... DDC 88 67 90 66 / 20 40 20 30 GCK 89 66 91 66 / 20 30 20 20 EHA 90 67 94 66 / 40 20 20 30 LBL 91 67 94 67 / 30 20 20 30 HYS 87 66 86 65 / 20 50 40 40 P28 90 68 90 69 / 10 30 30 40 && .DDC Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Umscheid LONG TERM...Umscheid AVIATION...JJohnson
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
500 AM CDT TUE JUN 28 2016 .SHORT TERM...(Today and Tonight) Issued at 411 AM CDT TUE JUN 28 2016 A complex of thunderstorms continued to move southeast early this morning, showing signs of intermittent severe downburst winds. Overall parameters are not particularly favorable for severe storms, but the organized cold pool has been able to interact with elevated instability and modest deep layer wind shear to provide periods of intensification and organization of rear inflow jets and downdraft surges. It is these features that will continue to be monitored for severe wind potential...and severe hail is a minimal secondary hazard along with locally heavy rain. These storms have become organized enough that they seem to be developing a convectively enhanced MCV aloft, and would expect this feature to move southeast with the storms and probably continue to enhance convection and rainfall rates...and also steer the motion of the storms a bit. Expect storms to gradually diminish and move out of the area by mid to late morning. Beyond that time, should see mainly dry conditions through the rest of the day. Additional storms will likely develop in Nebraska and move south and southeast into the evening but there is some uncertainty in whether they will have sufficient instability to progress into northeast KS, and chances seem pretty low. A more organized MCS is likely to develop farther west, and remain mainly west of the forecast area through the evening although the eastern fringes could stretch into north central KS. Then later on tonight, additional forcing moves across eastern Nebraska...and again may be able to support storms into central and eastern KS closer to sunrise but instability should be weak and severe potential seems quite low or nil from noon today at least through tonight. .LONG TERM...(Wednesday through Monday) Issued at 411 AM CDT TUE JUN 28 2016 Overall extended period remains unsettled with an active pattern of weak embedded troughs traversing through the region, bringing multiple chances for convection through Sunday. There are a few periods where confidence in precip increases with a more optimal forcing mechanism Thursday evening through Saturday evening. Otherwise, confidence is fairly low in coverage of pops - highly dependent on mesoscale factors that mid term models are unable to discern this far out. Convection on Wednesday afternoon and evening, mainly focuses over north central areas. Timing of convection on Tuesday evening will dictate this scenario as the NAM continues to be highlighting an MCS over western KS during this time, while other guidance focuses the activity further east towards central/north central areas during the early afternoon Wednesday. Will need to monitor highs as guidance may be trending too cool based on the coverage of precipitation and cloud cover. I raised highs a few degrees for now as current thinking sides with precip remaining mostly west of our area with mostly sunny skies in the late afternoon and temps in the middle 80s. Will likely see a break Wednesday evening before the cold front arrives from the west Thursday afternoon, providing a better source of lift for thunderstorms to develop. Lapse rates aloft remain weak while ample instability and effective shear values peak at around 40 kts, lending to a few strong to severe storms, especially along and south of the Interstate 70 corridor. Raised pops to likely south of Interstate 70 for this period as all guidance points to the boundary hanging up across southern KS with periods of thunderstorms redeveloping in the afternoon hours on Friday. Mid level flow becomes more westerly by this time, allowing for several vorticity lobes to track from the southwest through Saturday evening. Organized severe weather during this period is low, but cannot rule out isolated storms being on the stronger side. On the north side of the front, much of northeast Kansas remains on the cool side with highs in the lower 80s and lows in the 60s. On Sunday and Monday, while models are in large disagreement, there are trends in shortwave ridging aloft bring a temporary end to precip chances for the July fourth holiday. During the day, southerly flow returns along with the heat and humidity as readings rise in to the lower 90s. && .AVIATION...(For the 06Z TAFS through 06Z Tuesday Night) Issued at 1153 PM CDT MON JUN 27 2016 Will continue with VFR forecast. Still appears enough wind and cloud will keep BR/FG in check. Low probabilities of high-based precip exist much of this forecast, too low for any inclusion. && .TOP Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Barjenbruch LONG TERM...Prieto AVIATION...65
Area Forecast Discussion National Weather Service Goodland KS 330 AM MDT TUE JUN 28 2016 .SHORT TERM...(Today through Thursday night) Issued at 330 AM MDT Tue Jun 28 2016 Upper level high pressure centered over southern Utah early this morning with low pressure moving south into the Great Lakes. The upper high is forecast to gradually slide southeast into New Mexico tomorrow then into west Texas Thursday. Weather disturbances (per 700-500mb humidity) and associated showers/thunderstorms are forecast to move in from the north- northeast late this evening and continue overnight. Drier air aloft moves in during the day Wednesday with little if any precipitation expected. Depending on what model you believe we may see some showers and thunderstorms Wednesday night before tapering off after midnight. For Thursday through Thursday night precipitation chances increase as a more significant system moves southeast across much of the area. The models arent handling each weather disturbance very well thus timing and precipitation amounts vary. High temperatures today in the low 90s. Low temperatures in the upper 50s to low 60s. For Wednesday afternoon am expecting high temperatures to range from the mid 80s to around 90 along the KS/NE border as well as Norton and Hill City areas with low to mid 90s elsewhere. Low temperatures again in the upper 50s to low 60s. For Thursday noticeably cooler with afternoon temperatures in the mid 70s to mid 80s. Low temperatures in the mid 50s to low 60s. .LONG TERM...(Friday through Monday) Issued at 214 AM MDT Tue Jun 28 2016 The upper level flow over the CONUS, for the most part, has been consistent via the model runs over the past 3-4 days; with a ridge in the west, trough in the east and a trough starting to push into the Pacific Northwest. It was mentioned yesterday that by Friday the 500 mb flow was going to start shifting to a more west northwest flow, and this has held true again in the newest model runs (the European has a more zonal flow though compared to the GFS). This is due to the trough in the eastern CONUS becoming less amplified and moving more northeast and allowing the ridge to shift south. Due to this shift and upper level flow having a more westerly component, the model runs are now showing the higher chances for storms to be to the south of the CWA on Friday and Saturday. Yet, this does not mean the region will not get rain and storms, just the greatest instability and lift are to the south. Sunday and Monday look to be drier than the other days in the extended but Monday specifically has less of a chance for precipitation than Sunday. This is due to the ridge shifting again and engulfing the CWA. Overall, precip chances are still possible every day but start to diminish in the latter half of the extended. Temperatures will be in the 70s and 80s Friday before they begin to increase back into the 90s on Monday. && .AVIATION...(For the 12Z TAFS through 12Z Wednesday morning) Issued at 330 AM MDT Tue Jun 28 2016 KGLD...vfr conditions expected through the period. Will have to watch for an isolated storm around taf issuance as a cell is moving through KIML heading toward KGLD. Otherwise should see quite a bit of sunshine with winds becoming east-southeast then southeast at 10kts or less. Thunderstorm probabilities increase after about 00z and peak in the 03z-09z timeframe before decreasing. Severe weather and heavy rainfall possible which could produce mvfr cigs and/or visibilities. Winds remain from the southeast around 10kts but could see some higher gusts around 00z. KMCK...vfr conditions expected through the period. Similar to KGLD should see quite a bit of sunshine with winds from the southeast near 10kts. Thunderstorm probabilities increase after about 22z and peak in the 02z-07z timeframe. Severe weather and heavy rainfall possible which could produce mvfr cigs and/or visibilities. && .GLD Watches/Warnings/Advisories... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...99 LONG TERM...CLT AVIATION...99
Area Forecast Discussion National Weather Service Dodge City KS 326 AM CDT TUE JUN 28 2016 ...Updated Short Term and Long Term Sections... .SHORT TERM...(Today and tonight) Issued at 325 AM CDT Tue Jun 28 2016 The northwest flow pattern is underway, and along with it a challenging forecast. At the time of this writing at 0800 UTC, there were two small MCSs, one across far eastern Colorado and adjacent far western KS with a second one across far north central KS. It looks like a majority of the southwest KS region will avoid both of these MCSs as they track almost due south. The exception will be the western six counties were some rainfall of around a quarter inch can be expected with some locally higher amounts through the mid-morning hours before the MCS weakens. Some of the hourly HRRR runs want to merge the two MCSs, so that will have to be watched later in the morning, but right now that doesn`t seem to be happening, so we will be keeping POPs fairly low with the exception of far southwest and west central KS. It is unclear exactly how convection will evolve late this afternoon through tonight. We could see a repeat of yesterday, except starting off a bit farther north in Nebraska. A mature MCS never really materialized last night like was forecast, however that does not mean that one large, cohernet, long-lived MCS won`t happen tonight. Signals are certainly there in both the high resolution convective allowing models and lower resolution models. The NAM12 is particularly bullish, showing a significant QPF signal rolling SSE from western Nebraska into southwest KS by 12z Wednesday. Both the NCEP WRF-ARW and WRF-NMMB show something coherent rolling across the same generally area before decaying around or shortly after 09z Wednesday. In the official forecast, we will have 40-50 POPs going mainly east and north of a Dighton-Dodge-Greensburg-Pratt line with greatest confidence and QPF forecast values up along the I-70 corridor. .LONG TERM...(Wednesday through Monday) Issued at 325 AM CDT Tue Jun 28 2016 The active northwest flow pattern will continue through the end of the week. A couple of things that will probably act to enhance precipitation coverage and intensity later in the week will be 1) a fairly decent surface front which will slow down and perhaps become quasi-stationary across southern Kansas and 2) some minor mid level perturbations/enhanced mid level moisture rotating around weak ridging, thanks to abundance of mountain convection across the southern Rockies. POPs in the Long Term will be highest Thursday Night through Saturday Night with 12-hr POPs every period in the 40- 60 percent territory somewhere across our forecast area from west central KS through south central KS. It still looks as though some areas will see potentially excessive rainfall once the polar front gets down here, given all the moisture that will be around and the generally weak mid-upper level flow leading to slow-moving convection. && .AVIATION...(For the 06Z TAFS through 06Z Tuesday night) Issued at 1216 AM CDT Tue Jun 28 2016 Will be playing the TAFs fairly conservatively given the fact that it is difficult to latch on to any coherent convective signal for much of the forecast period. That said, the near term HRRR solution does suggest a small thunderstorm cluster moving south from the Goodland area, clipping the GCK area overnight, so we will include a 3 hour period of VCTS at that terminal, but elsewhere (DDC and HYS) we will keep the TAFs free of convection until there is something concrete to latch onto. A rather large MCS may drive south late tomorrow evening affecting much of western Kansas, but since this is at the very end of this forecast cycle, we will not introduce the threat into the TAF yet. && .PRELIMINARY POINT TEMPS/POPS... DDC 88 67 90 66 / 20 40 20 30 GCK 89 66 91 66 / 20 30 20 20 EHA 90 67 94 66 / 40 20 20 30 LBL 91 67 94 67 / 30 20 20 30 HYS 87 66 86 65 / 20 50 40 40 P28 90 68 90 69 / 10 30 30 40 && .DDC Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Umscheid LONG TERM...Umscheid AVIATION...Umscheid
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
1154 PM CDT MON JUN 27 2016 ...Update to aviation forecast discussion... .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 06Z TAFS through 06Z Tuesday Night) Issued at 1153 PM CDT MON JUN 27 2016 Will continue with VFR forecast. Still appears enough wind and cloud will keep BR/FG in check. Low probabilities of high-based precip exist much of this forecast, too low for any inclusion. && .TOP Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Gargan LONG TERM...Wolters AVIATION...65
AREA FORECAST DISCUSSION
National Weather Service BILLINGS MT
814 PM MDT WED JUN 29 2016 .UPDATE... A few isolated thunderstorms made their way through the area this evening, resulting in the issuance of a few SPS` and one warning. Most of the reports resulted in small hail some much needed rain. Unfortunately, the rain only impacted a very, very small portion of the region, mainly over Wheatland and Golden Valley Counties. For this evening update, only decided to make a few changes to the going forecast. Went ahead and upped the pops to 20 percent or greater across the western and central zones to account for an occasional air mass thunderstorm that may pop up overnight. Otherwise, the going forecast looks good, with high temps in the 80s and 90s tomorrow. Singer && .SHORT TERM...valid for Thu and Fri... Isolated convection has developed across our cwa this afternoon in response to diurnal destabilization and very weak energy in WNW flow aloft. Activity has been mostly over the high terrain with the exception of a line of showers/tstms from north of Roundup to Baker and Ekalaka. A couple storms became briefly severe in Fallon county earlier this afternoon, and there exists a fairly strong storm near 3HT as of 230 pm. Latest mesoanalysis shows CAPES climbing up to 1000-1500 J/KG, with effective bulk shear from 35-45 kts. This is enough for strong to severe storms but forcing is rather weak and HRRR soundings continue to show some modest mid level capping, and we are starting to mix some drier air as dew pts have fallen a bit since midday. SO, could see a strong to perhaps severe storm over the next few hours but we are not anticipating widespread severe wx. Some degree of stabilization should occur in our east tonight as weak pressure rise builds out of southern Saskatchewan. Could see a few showers/tstms persist thru the night and into early Thursday courtesy of PV emerging from ID and an easterly low level jet nosing as far west as Harlowton and Columbus. While our far east should remain dry and capped on Thursday, as sfc ridge settles over the northern plains, convective chances should increase in our west as next shortwave moves in from the west. Not a big severe threat but could see a few strong storms in our west Thursday afternoon with an enhanced easterly wind across our cwa. Activity will spread east thru the night as a bit stronger llj affects our eastern zones, with some showers/tstms possible in our east late Thursday night and Friday morning. Convective potential may decrease a bit Friday under shortwave ridging, but moisture and instability will remain in place so slight pops should suffice across the cwa during the afternoon and evening. Temps will remain above normal but not in an extreme sense. Expect highs in the 80s to lower 90s each of the next couple days. JKL .LONG TERM...valid for Sat...Sun...Mon...Tue...Wed... Saturday a weak shortwave pushes eastward of the area as another more significant shortwave approaches from the west. Temps will push into the low to mid 90s on Saturday with westerly and southerly flow at the surface. Frontal forcing will allow for areas of chance pops over central Montana for Saturday afternoon and evening. Slight chance of PoPs will remain over the mountain areas on Sun and Mon with weak forcing across much of the area. It is not until later in the week when perhaps a more significant front will move in which could bring more widespread rain chances. Overall, temperatures should remain fairly stagnant through the forecast with upper 80s and low 90s during the day and 50s and 60s for lows in the valleys and along the Plains. Still hedging a little warmer than guidance on Wednesday because there remains uncertainty with position of upper-level disturbance. Walsh && .AVIATION... Easterly winds should prevail at all terminals with a slight chance of an isolated thunderstorm near KLVM or KBIL overnight. Conditions should remain VFR for the rest of the period. Singer && .PRELIMINARY POINT TEMP/POPS... Thu Fri Sat Sun Mon Tue Wed ----------------------------------------------------------- BIL 060/087 060/091 062/093 061/091 059/090 059/089 058/086 22/T 32/T 22/T 22/T 22/T 22/T 22/T LVM 053/084 051/090 052/090 050/088 048/087 048/086 047/083 33/T 32/T 22/T 22/T 22/T 22/T 22/T HDN 057/088 059/090 059/093 057/092 056/090 055/091 054/087 22/T 22/T 22/T 22/T 21/U 11/B 12/T MLS 060/085 062/090 062/093 062/091 060/090 060/089 059/087 21/B 22/T 22/T 32/T 22/W 12/T 22/T 4BQ 058/085 060/087 060/094 062/094 060/093 059/094 058/090 21/B 23/T 22/W 22/T 22/W 11/B 22/W BHK 054/080 055/083 057/089 058/091 057/089 056/089 056/085 21/B 23/T 22/T 22/T 22/T 22/T 22/T SHR 055/086 055/088 055/092 054/092 053/091 053/091 053/088 32/T 22/T 22/T 22/T 21/B 11/B 12/T && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$ weather.gov/billings Area Forecast Discussion National Weather Service Flagstaff AZ 243 AM MST THU JUN 30 2016 .SYNOPSIS...Expect active monsoon weather through Saturday with good coverage of showers and thunderstorms each day. Starting Sunday a drier westerly flow across Arizona will bring a downturn in activity heading into the first part of next week. && .DISCUSSION...High pressure centered over New Mexico this morning will slowly slide into Texas over the next 24 to 48 hours. The position to the high will allow monsoon moisture to continue streaming into northern Arizona. For today...Almost too much moisture, especially in the mid levels. At least early on clouds are apt to suppress stronger convective activity, perhaps lasting the whole day. Still expect good coverage of showers and storms but generally a lower chance of intense downpours along and east of a line extending from Prescott to the Grand Canyon. West of this line there could be a bit more sunshine with stronger instability developing along with an isolated 1 to 2 inch drencher possible. On Friday...Moisture will remain across northern Arizona. Some models are indicating that the mid levels could dry some for more sunshine with more moisture in the lower levels. If this pans out stronger storms will be more numerous on Friday. Starting Saturday and lasting into next week...A drying and stabilizing west to southwest will develop. Enough moisture will linger on Saturday for another round of scattered showers and storms. In fact, the vertical wind profile suggests a better potential for an isolated storm or two to become severe on Saturday. Beyond Saturday the drying and stabilizing trend will take hold with just a slight chance of showers and thunderstorms each day. && .AVIATION...For the 12Z Package...Scattered -SHRA through the morning hours. Scattered to numerous TSRA developing aft 17Z. Locally heavy rain may produce MVFR/IFR conditions with small hail also possible. Gusty winds in excess of 40 kts possible in the lower terrain of central AZ (south of the Mogollon Rim). Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Scattered to numerous showers and thunderstorms are expected through Friday. Any storms will be capable of producing locally heavy rain, with gusty outflow winds also possible. The increased clouds and showers will keep daytime temperatures below average. Saturday through Monday...Expect the active monsoon pattern to continue through Saturday, followed by a downturn Sunday and Monday as drier westerly flow develops. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC...McCollum AVIATION...MCS For Northern Arizona weather information visit weather.gov/flagstaff
Area Forecast Discussion National Weather Service Flagstaff AZ 936 PM MST WED JUN 29 2016 .SYNOPSIS...Expect an active wet monsoon pattern through Saturday as the position of the high pressure ridge allows deep moisture to move into Arizona from the south. Abundant moisture and convective instability will produce good coverage of showers and thunderstorms each day. A deep trough will move into the western states over the weekend. A drier southwesterly flow across Arizona will bring a down turn in shower and thunderstorm activity heading into the first half of next week. && .DISCUSSION...Numerous showers and thunderstorms developed today across central Arizona along and south of the Mogollon Rim region. Heavy localized rainfall at times required issuance of several small stream flood advisories and a few flash flood warnings. The most significant flash flood report was for a 4 to 5 foot rise of water along the Cedar Creek basin just south of the Cedar Fire burn area on the White Mountains Apache Tribe reservation. An active wet monsoon pattern over the next few days will continue to produce scattered to numerous showers and thunderstorms each afternoon through Saturday. The position of the subtropical ridge will favor deep southeasterly moisture advection. Precipitable Water amounts will hover around 1 inch for the next few days, which favors abundant shower and thunderstorm activity across northern Arizona. The main threats will be lightning, erratic gusty winds at times near heavier shower bands, and the potential for localized flash flooding. Sunday through Wednesday...A mid-latitude trough moving into the western states will bring drier southwesterly flow into Arizona. This drier flow pattern will lower humidity levels and significantly reduce shower and thunderstorm activity. && .AVIATION...For the 06Z Package...Thunderstorm activity has moved into southern Arizona this evening. Showers and Thunderstorms will redevelop on Thursday after 18Z. Locally heavy rain, small hail, and erratic gusty winds are possible with these 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 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...Bohlin AVIATION...Bohlin FIRE WEATHER...JJ For Northern Arizona weather information visit weather.gov/flagstaff
Area Forecast Discussion National Weather Service Flagstaff AZ 936 PM MST WED JUN 29 2016 .SYNOPSIS...Expect an active wet monsoon pattern through Saturday as the position of the high pressure ridge allows deep moisture to move into Arizona from the south. Abundant moisture and convective instability will produce good coverage of showers and thunderstorms each day. A deep trough will move into the western states over the weekend. A drier southwesterly flow across Arizona will bring a down turn in shower and thunderstorm activity heading into the first half of next week. && .DISCUSSION...Numerous showers and thunderstorms developed today across central Arizona along and south of the Mogollon Rim region. Heavy localized rainfall at times required issuance of several small stream flood advisories and a few flash flood warnings. The most significant flash flood report was for a 4 to 5 foot rise of water along the Cedar Creek basin just south of the Cedar Fire burn area on the White Mountains Apache Tribe reservation. An active wet monsoon pattern over the next few days will continue to produce scattered to numerous showers and thunderstorms each afternoon through Saturday. The position of the subtropical ridge will favor deep southeasterly moisture advection. Precipitable Water amounts will hover around 1 inch for the next few days, which favors abundant shower and thunderstorm activity across northern Arizona. The main threats will be lightning, erratic gusty winds at times near heavier shower bands, and the potential for localized flash flooding. Sunday through Wednesday...A mid-latitude trough moving into the western states will bring drier southwesterly flow into Arizona. This drier flow pattern will lower humidity levels and significantly reduce shower and thunderstorm activity. && .AVIATION...For the 06Z Package...Thunderstorm activity has moved into southern Arizona this evening. Showers and Thunderstorms will redevelop on Thursday after 18Z. Locally heavy rain, small hail, and erratic gusty winds are possible with these 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 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...Bohlin AVIATION...Bohlin FIRE WEATHER...JJ For Northern Arizona weather information visit weather.gov/flagstaff
  [top] Area Forecast Discussion National Weather Service Tucson AZ 920 PM MST WED JUN 29 2016 .SYNOPSIS...Expect periods of 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 few showers and thunderstorms mainly east of Tucson next Monday and Tuesday. Cooler temperatures will occur, especially Friday, then warmer temperatures will return early next week. && .DISCUSSION...Strong storms this afternoon as strong outflows helped some valley locations take advantage of above average convective potential and moisture for late June. Several examples of wind gusts in excess of 55 mph and 1 inch hail. Due to the nice easterly flow, additional outflows, and some remaining untapped elevated CAPE we will be prone to shower and thunderstorm activity across the area through the early morning hours. Another round of storms is in the offing Thursday. After lingering debris and shower activity, expect the mid level impulse that helped trigger the large MCS immediately to our south to continue to assist thunderstorm development along with strong outflows and very deep moisture. Elevated risk for isolated severe and heavy rainfall Thursday and Friday. We made minor adjustments based on early 00z analysis and model returns, including beefing up coverage for convection over the next 24 hours. Please see the previous discussion below for additional details. && AVIATION...VALID THRU 31/06Z. Showers with isolated thunderstorms will continue to be in the vicinity of terminals overnight, and then again Thursday. Gusty winds and brief MVFR conditions in heavy rainfall are likely near storms. 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. && .PREV DISCUSSION...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. && .TWC WATCHES/WARNINGS/ADVISORIES... None. && $$ Meyer/French Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
  [top] Area Forecast Discussion National Weather Service Phoenix AZ 850 PM MST WED JUN 29 2016 .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... Scattered storms have been percolating through much of southern and central Arizona this afternoon and early evening tied to rich moisture profiles, adequate instability, and broad synoptic ascent structures. 00Z KTWC sounding sampled excellent 11-12 g/kg boundary layer moisture profiles with total column Pwats above 1.50 inches and MLcape approaching 1500 J/kg. Though the KPSR sounding failed, objective analysis suggests 10-11 g/kg and Mlcape closer to 1000 J/kg, and current radar returns support this analysis. Thus far, lift has been mainly along better outflow boundaries and through orographic ascent, though this may be rapidly changing. Per objective analysis, dynamical fields are improving with a distinct H7 trough passing into central AZ and upper difluence becoming more pronounced. Radar loops reflect this improving convective environment with organized deeper outflow and hints of an MCV propagating through Gila County. This added lift along with colliding outflow boundaries through the Phoenix metro may allow more numerous storms to form mid to late evening. This is already starting to become evident in radar imagery. Made some modest adjustments to pops given current radar trends, and may need to increase values further over the metro while also extending better chance beyond midnight. .PREVIOUS DISCUSSION... /252 PM MST WED JUN 29 2016/ 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: Numerous outflow boundaries will continue to yield frequently shifting winds through the evening and overnight, though eventually storms to the east should allow for a stronger easterly gradient. Still have held the VCTS mention into terminal sites as environment is favorable for storms. Confidence on coverage and specific direct impact to airfields is low. Several high resolution models suggest showers re-entering the picture very late tonight and Thursday morning with cigs falling below 8K ft, but yet staying above 6K ft. Regardless of Shra potential, it appears some measure of these cigs are probable with an easterly wind component predominating. 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 20kt while only sct mid/high clouds pass through the area tonight. Somewhat lower scattered clouds will be possible Thursday. 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...None. && $$ Visit us on Facebook...Twitter...and at weather.gov/phoenix DISCUSSION...MO/AJ/CB AVIATION...MO FIRE WEATHER...Hernandez
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
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
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
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
401 AM CDT THU JUN 30 2016 .SHORT TERM...(Today and Tonight) Issued at 355 AM CDT THU JUN 30 2016 Remnants of yet another overnight MCS were weakening and moving into north central KS at 330 AM while other widely scattered thunderstorms had been developing in far eastern KS mainly east of HWY 75. The north central KS activity should ease into parts of the local forecast area, but will probably remain west of a Belleville to Abilene line through sunrise. One question for the day will be if any remnants MCV from this system can maintain scattered thunderstorms as it drifts into the area this morning. There is also a secondary thunderstorm complex moving southeast on the boundary set up by this initial MCS, and while it will most likely point south of the local area will want to keep an eye on the evolution over the next few hours. Meanwhile the eastern KS activity, driven by weak isentropic ascent in an uncapped MU Parcel atmosphere, should persist for at least a few hours with a very gradual shift to the east and south as the weak LLJ veers and the focus shifts. None of this thunderstorm activity through sunrise is expected to be severe, but brief storm organization into stronger updrafts is not out of the question. Storms in these areas may persist beyond sunrise, but better chances for a few strong storms may focus this afternoon. Expect another warm day well into the 80s and similar to Wednesday although again somewhat dependent upon cloud cover. This will support moderate destabilization with 25 to 30 kts of 0-6 km shear. A cool front will push into the area from the north while surface low pressure will deepen in southeast Colorado with a surface trough extending into east central KS. Will see increasing convergence along this surface trough and the incoming front which will probably lead to scattered thunderstorm development by around mid day, mainly near/south of I-70. A few of these storms could become severe with damaging wind and marginally severe hail. They should also produce outflow which should help the front progress south of the forecast area by this evening. The zone north of this front should then become the focus for elevated thunderstorm development by late evening as a modest low level jet converges with elevated parcels having little to no inhibition. Expect one focus for storms to be basically along the southwest border of the coverage area from Minneapolis down through Burlington. Severe storms are unlikely with this activity given only modest instability, but the convective focus could be slow to move and areas of locally heavy rain will be possible. The relatively dry ground conditions suggest that flash flood guidance is unlikely to be met through tonight but will be something to keep an eye on. Regardless, this may be a precursory rain to set up flooding potential with the additional heavy rains at the end of the week. .LONG TERM...(Friday through Wednesday) Issued at 355 AM CDT THU JUN 30 2016 Overall confidence is increasing for periods of thunderstorms, heavy rainfall, and flooding for much of the area this weekend. Given the consistency of the models, favorable setup synoptically, and the impacts from the holiday weekend, have issued a Flash Flood Watch for the entire northeast Kansas area Friday evening through Sunday. Details to follow. Overnight convection may linger into Friday morning for north central areas, however with the waning low level jet believe there will be a break from precipitation for much of the cwa Friday afternoon before an organized mid level trough enters western Kansas Friday evening. All guidance continues to support showers and thunderstorms developing over central KS, gradually tracking east into northeast KS after midnight through the day Saturday. Have increased pops for this period in the 70-80% range. Forecast soundings highlight the heavy rainfall potential given the strong moisture flux into the area, rising PWAT values over 2 inches and cloud tops warming to over 13 kft. Could see more widespread convective precipitation redevelop Saturday afternoon and evening as MUCAPE values increase in excess of 2000 J/KG and bulk shear values are in the 35 to 40 kt range. A few of these storms may become severe with mainly hail and damaging wind gusts. Heaviest precipitation begins to slowly shift eastward on Sunday, affecting east central areas. The most concerning hazard for the weekend is the flooding potential across the entire area. Forecast QPF amounts have consistently ranged in the 2 to 4 inch range, although it is likely for some locations to receive up to 6 inches of rainfall by Sunday evening. It is too difficult to discern where these locations will be, however confidence is high enough for the widespread rainfall to cause flooding issues and have therefore issued a Flash Flood Watch in coordination with the Kansas City office. Temperatures over the weekend remain well below normal with highs in the lower 80s and lows in the lower 60s. This is still above the very cool guidance that models have not handled well this past week. Temporary, shortwave ridging builds over the western high plains, placing a temporary hold on widespread thunderstorms for the Fourth of July. Could still see a few thunderstorms in the evening, especially over central KS, but overall should remain dry with highs in the lower to middle 80 and overnight lows in the upper 60s. Weak troughing embedded within the westerly flow aloft will continue to bring scattered thunderstorms into the region Tuesday and Wednesday. Confidence is not high with the GFS and ECMWF still depicting varying solutions. Southerly flow and moisture return seems to be a better bet with highs back into the 90s and dewpoints in the 70s. && .AVIATION...(For the 06Z TAFS through 06Z Thursday Night) Issued at 1152 PM CDT WED JUN 29 2016 VFR conditions are expected through the period. Thunderstorms across Nebraska are expected to move to the southeast through 12Z. Confidence in timing at the terminals is low, and most short term models weaken the complex or keep it to the west of MHK. Will leave out of the tafs for now. Development of additional tsra is possible after 00Z Friday and may affect the MHK terminal after 03Z. Winds light and variable becoming light north to northeast after 18Z. && .TOP Watches/Warnings/Advisories... Flash Flood Watch from Friday evening through Sunday evening for KSZ008>012-020>024-026-034>040-054>056-058-059. && $$ SHORT TERM...Barjenbruch LONG TERM...Prieto AVIATION...53
  [top] Area Forecast Discussion National Weather Service Goodland KS 228 AM MDT THU JUN 30 2016 .UPDATE... Issued at 1122 PM MDT Wed Jun 29 2016 With the storm activity moving south of the area have cancelled the severe thunderstorm watch. North of the Tri-State Area a new round of storms will impact the area during the overnight hours. The storm activity may last into the early morning hours if the storms in the Nebraska Panhandle make it this far south. Main threat with the storms overnight will be large hail although severe wind gusts cannot be ruled out. && .SHORT TERM...(This evening through Thursday) Issued at 157 PM MDT Wed Jun 29 2016 As of 3 PM CDT/2 PM MDT, skies across the Tri-State Region are mostly clear. A few cumulus clouds have recently developed over east Colorado and extreme northwest Kansas. Temperatures are in the mid to upper 80s for most locations. Winds are generally less than 10 mph for most locations. However, south winds are beginning to pick up to 10-15 mph, gusting to 20 mph. At the surface, an area of low pressure was located along the Colorado Front Range. A weak front/remnant outflow boundary is located across eastern Colorado. Aloft, a shortwave trough is moving across Colorado. Thunderstorms have developed over the Rockies ahead of this trough. For this evening and tonight, am expecting another round of strong to severe thunderstorms to move across the region. High resolution guidance, while varying somewhat amongst each piece of guidance, suggest that storms develop this afternoon over eastern Colorado and Wyoming. Then, as the evening progresses, storms should coalesce into another complex or two, spreading southeast across the Tri- State Region. Storms should exit the region after midnight. Overall, am not anticipating quite the storm intensity as last night as the atmosphere has been worked over some. Current mesoanalysis does indicate SBCAPE up to 2500 J/KG in some locations but a cap persists. When the cap breaks, strong/severe thunderstorms should quickly develop. In addition, strong shear remains (0-6 KM Bulk Shear is 40-50 kts). Therefore, anticipating the primary threat with these storms to be damaging winds once again. Any initial development will be capable of large hail, very large possible. Further, recent heavy rains have saturated the soils for some locations. These locations, if they receive additional heavy rain from thunderstorms, would be prone to flash flooding tonight. Was not confident enough to issue a flash flood watch at this time due to some disagreement in guidance with regards to the movement of this complex. For tomorrow, a cold front should push south across the region. As a result of the front and likely extensive cloud cover, cooler temperatures are forecast. Instability parameters remain favorable for some strong/severe thunderstorms, particularly later in the afternoon hours. Thinking the highest chances for thunderstorms (in the afternoon) will be along/west of a line from Benkelman, Nebraska to Tribune, Kansas. Large hail and damaging winds will be possible. Winds aloft should weaken so slower storm movement appears likely. In addition, precipitable water content increases. Therefore, heavy rain and flash flooding may become an issue. .LONG TERM...(Sunday through Wednesday) Issued at 227 AM MDT Thu Jun 30 2016 H5 trough axis moves east on Sunday and pulls the better rain chances with it. PoPs remain in the eastern portions of the CWA through the afternoon with an isolated thunderstorm or two possible elsewhere. Another weak shortwave and associated axis of instability will move across the region Monday with slgt chc to chc PoPs mainly during the afternoon to early evening. Tuesday we will see good moisture transport at the 850mb level out of the south which will combine with ample instability during the afternoon and early evening to trigger thunderstorm development in the presence of weak forcing. For Wednesday and Thursday, weak shortwave ridge builds and moves east. This will serve to cut off the moisture flow at the 850mb to 700mb level and dry things out across the CWA. There will be instability in the region; however, with little forcing there will be little to no chance of thunderstorm development. The global models are both highlighting the beginnings of a monsoonal type trough development in the southwest late in the extended period which will increase the PoPs once more but will need to see better consistency before committing to higher rain chances. && .AVIATION...(For the 06Z TAFS through 06Z Thursday night) Issued at 1122 PM MDT Wed Jun 29 2016 VFR conditions expected for the TAFs. Main issue in the near term will be the line of storms that recently formed north of KMCK. This line of storms will impact the site around 630z and may linger over the site for an hour. Am expecting breezy winds and moderate to possibly heavy rainfall with some hail. During the late afternoon storm activity approaching from the northwest may impact the TAF sites, particularly KGLD. && .GLD Watches/Warnings/Advisories... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...JTL SHORT TERM...RRH LONG TERM...TL AVIATION...JTL
  [top] Area Forecast Discussion National Weather Service Dodge City KS 326 AM CDT THU JUN 30 2016 ...Updated long term section... .SHORT TERM...(Today and tonight) Issued at 239 AM CDT Thu Jun 30 2016 A slight chance of thunderstorms will exist this morning across central Kansas as the remnants of a MCS moves south out of Nebraska and into Kansas. Otherwise, expect decreasing cloudiness this morning becoming partly cloudy this afternoon. Thunderstorm chances increase once again late afternoon into the overnight period as an upper level shortwave moves up and over an upper level ridge located over the southern Rockies. Skies will become mostly cloudy tomorrow night as the thunderstorm activity rolls through the area. At the surface, an area of low pressure will be located across southeastern Colorado today with a stationary front bisecting Kansas. This will lead to south to southeasterly winds across the southern half of the CWA shifting to more of an easterly direction across the northern half of the CWA. Winds shift to more of an easterly direction tonight as the frontal boundary gets pushed to the south. As for temperatures, highs today look to reach into the upper 80s to around 90 degrees with lows tonight ranging from the lower 60s across eastern Colorado to upper 60s across south central Kansas. .LONG TERM...(Friday through Wednesday) Issued at 325 AM CDT Thu Jun 30 2016 Thunderstorm chances continue into the weekend as a series of disturbances move through the area. Flow aloft will generally be from the northwest initially becoming more zonal this weekend. Ample moisture in the low to mid levels of the atmosphere will bring partly to mostly cloudy skies to western Kansas through this weekend. Towards the surface, an area of low pressure will continue to be confined southwest of the area with a frontal boundary extending eastward along the KS/OK border. This will lead to east to southeasterly direction Friday shifting to more of a northeasterly direction this weekend. A ridge of high pressure builds into the area during the first part of next week. Thunderstorms will be possible during the afternoon and evening hours, however, they should be more isolated than what we are expecting into this weekend. As for temperatures, highs will generally be in the 80s into this weekend reaching into the 90s next week. Lows look to dip into the 60s. && .AVIATION...(For the 06Z TAFS through 06Z Thursday night) Issued at 1151 PM CDT Wed Jun 29 2016 Scattered showers are currently moving through far western Kansas but are expected to stay west of the GCK terminal. I did place VCTS in the TAFs to account for the close proximity. Otherwise, VFR conditions will prevail with increasing mid level clouds. Winds will generally be from the south to southeast at less than 10 knots. A better chance of thunderstorms are possible tomorrow night, especially around the HYS terminal. && .PRELIMINARY POINT TEMPS/POPS... DDC 89 65 84 65 / 40 60 50 50 GCK 88 65 83 64 / 40 50 50 50 EHA 90 63 87 66 / 40 50 40 40 LBL 91 65 89 68 / 40 50 40 40 HYS 86 64 79 63 / 40 60 60 60 P28 91 68 87 68 / 40 70 50 50 && .DDC Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Hovorka_42 LONG TERM...Hovorka_42 AVIATION...Hovorka_42
  [top] Area Forecast Discussion National Weather Service Wichita KS 243 AM CDT THU JUN 30 2016 .SYNOPSIS... Issued at 241 AM CDT Thu Jun 30 2016 In the upper levels, currently have a deep trough situated over eastern Canada into the northeast CONUS with some shortwave energy diving southeast across southern Manitoba/western Ontario. At the surface, strong cold front stretches from northern MN through southern ND. Meanwhile, high pressure is centered over the Ohio/Tennessee Valley. && .SHORT TERM...(Today through Saturday night) Issued at 241 AM CDT Thu Jun 30 2016 Just like the last few nights, we are watching an mcs push south across southern Nebraska/northern KS with the big question how far south and east it will make it this morning. At this point it looks like at least central KS will get in on some precip this morning but still not sold it will make it down to south central KS based on how things have paned out the last few days. Outside of the activity this morning, confidence is low that we`ll see any additional development today, especially since the front doesn`t look like it will make it as far south as models projected yesterday. So one of the more significant changes to the going forecast was to knock down pops quite a bit for today. The better MCS activity will arrive tonight as the upper pattern starts to flatten out, which will allow the dirty moonsonal flow to spill into the area. Low levels will respond to this with an overnight low level jet which will also increase moisture transport in the 850-700mb layer. Confidence is high that storms will either develop out over the high Plains late this afternoon and move into the forecast area tonight or storms will develop on the low level jet this evening over west-central KS. Regardless of which scenario pans out, much of the forecast area should see rain tonight and with precipitable water values around 2 inches, any strong shower or storm will produce very high rainfall rates. The overnight activity should linger Fri morning, especially over the northeast portion of the forecast area. The same basic setup will be in play Fri night with the better moisture transport and low level jet convergence lifting slightly north. This would place the better heavy rain potential Fri night into Sat morning over central KS. There is still decent agreement between the ECMWF and GFS in a more robust upper wave sliding across the forecast area Sat through Sun. This will produce another round of widespread showers and storms with heavy rainfall and flooding still looking like the main threat as we maintain a very tropical airmass. .LONG TERM...(Sunday night through Wednesday) Issued at 241 AM CDT Thu Jun 30 2016 By Sun night the upper impulse will be situated over far eastern KS/western MO with the bulk of the rain chances out of the forecast area by Mon morning, with most of the area remaining dry for the 4th. Will run with some small storm chances Mon night through Tue night but confidence in this panning out is very low as there isn`t a significant upper wave or front to key on. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 942 PM CDT Wed Jun 29 2016 Thunderstorms will continue to move eastward from western Kansas and southward across Nebraska tonight, however the activity is expected to decrease as it approaches central Kansas late tonight. Winds will remain light during the day on Thursday and back to the east/southeast direction later in the afternoon. More numerous thunderstorms will develop over western Kansas Thursday afternoon/evening and spread into central Kansas. && .PRELIMINARY POINT TEMPS/POPS... Wichita-KICT 71 90 69 85 / 10 30 60 50 Hutchinson 70 89 68 83 / 20 30 60 50 Newton 69 89 68 82 / 20 30 60 50 ElDorado 70 90 69 83 / 10 30 60 50 Winfield-KWLD 71 91 70 85 / 10 40 60 50 Russell 68 88 66 79 / 30 30 70 50 Great Bend 69 88 66 81 / 20 30 70 50 Salina 69 88 67 80 / 20 20 50 50 McPherson 69 89 67 82 / 20 30 50 50 Coffeyville 70 91 71 84 / 20 30 60 60 Chanute 69 89 70 83 / 20 30 60 60 Iola 69 88 69 82 / 20 30 60 60 Parsons-KPPF 69 90 70 84 / 20 30 60 60 && .ICT Watches/Warnings/Advisories... None. && $$ SHORT TERM...RBL LONG TERM...RBL AVIATION...CDJ
Area Forecast Discussion National Weather Service Dodge City KS 239 AM CDT THU JUN 30 2016 ...Updated short term section... .SHORT TERM...(Today and tonight) Issued at 239 AM CDT Thu Jun 30 2016 A slight chance of thunderstorms will exist this morning across central Kansas as the remnants of a MCS moves south out of Nebraska and into Kansas. Otherwise, expect decreasing cloudiness this morning becoming partly cloudy this afternoon. Thunderstorm chances increase once again late afternoon into the overnight period as an upper level shortwave moves up and over an upper level ridge located over the southern Rockies. Skies will become mostly cloudy tomorrow night as the thunderstorm activity rolls through the area. At the surface, an area of low pressure will be located across southeastern Colorado today with a stationary front bisecting Kansas. This will lead to south to southeasterly winds across the southern half of the CWA shifting to more of an easterly direction across the northern half of the CWA. Winds shift to more of an easterly direction tonight as the frontal boundary gets pushed to the south. As for temperatures, highs today look to reach into the upper 80s to around 90 degrees with lows tonight ranging from the lower 60s across eastern Colorado to upper 60s across south central Kansas. .LONG TERM...(Thursday night through Wednesday) Issued at 305 PM CDT Wed Jun 29 2016 For the period of Thursday night into next Wednesday, an ongoing convective complex of storms may be moving across parts of western Kansas Thursday night with aggravated northwest flow aloft. For Friday northwest flow aloft begins to transition to more zonal flow with more shortwaves forecast into Sunday across the Western High Plains. Will keep fairly high chances going for rainfall, and areas of heavy rainfall still look good. After Sunday, rainfall chances decrease as the main upper jet and any shortwaves move north. Highs will be cooler and in the 80s into Sunday, but then warm back into the 90s by mid week next week. Lows will be mainly in the 60s then warm to around 70 after Monday. && .AVIATION...(For the 06Z TAFS through 06Z Thursday night) Issued at 1151 PM CDT Wed Jun 29 2016 Scattered showers are currently moving through far western Kansas but are expected to stay west of the GCK terminal. I did place VCTS in the TAFs to account for the close proximity. Otherwise, VFR conditions will prevail with increasing mid level clouds. Winds will generally be from the south to southeast at less than 10 knots. A better chance of thunderstorms are possible tomorrow night, especially around the HYS terminal. && .PRELIMINARY POINT TEMPS/POPS... DDC 89 65 84 65 / 40 60 50 50 GCK 88 65 83 64 / 40 50 50 50 EHA 90 63 87 66 / 40 50 40 40 LBL 91 65 89 68 / 40 50 40 40 HYS 86 64 79 63 / 40 60 60 60 P28 91 68 87 68 / 40 70 50 50 && .DDC Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Hovorka_42 LONG TERM...Kruse AVIATION...Hovorka_42
Area Forecast Discussion National Weather Service Dodge City KS 239 AM CDT THU JUN 30 2016 ...Updated short term section... .SHORT TERM...(Today and tonight) Issued at 239 AM CDT Thu Jun 30 2016 A slight chance of thunderstorms will exist this morning across central Kansas as the remnants of a MCS moves south out of Nebraska and into Kansas. Otherwise, expect decreasing cloudiness this morning becoming partly cloudy this afternoon. Thunderstorm chances increase once again late afternoon into the overnight period as an upper level shortwave moves up and over an upper level ridge located over the southern Rockies. Skies will become mostly cloudy tomorrow night as the thunderstorm activity rolls through the area. At the surface, an area of low pressure will be located across southeastern Colorado today with a stationary front bisecting Kansas. This will lead to south to southeasterly winds across the southern half of the CWA shifting to more of an easterly direction across the northern half of the CWA. Winds shift to more of an easterly direction tonight as the frontal boundary gets pushed to the south. As for temperatures, highs today look to reach into the upper 80s to around 90 degrees with lows tonight ranging from the lower 60s across eastern Colorado to upper 60s across south central Kansas. .LONG TERM...(Thursday night through Wednesday) Issued at 305 PM CDT Wed Jun 29 2016 For the period of Thursday night into next Wednesday, an ongoing convective complex of storms may be moving across parts of western Kansas Thursday night with aggravated northwest flow aloft. For Friday northwest flow aloft begins to transition to more zonal flow with more shortwaves forecast into Sunday across the Western High Plains. Will keep fairly high chances going for rainfall, and areas of heavy rainfall still look good. After Sunday, rainfall chances decrease as the main upper jet and any shortwaves move north. Highs will be cooler and in the 80s into Sunday, but then warm back into the 90s by mid week next week. Lows will be mainly in the 60s then warm to around 70 after Monday. && .AVIATION...(For the 06Z TAFS through 06Z Thursday night) Issued at 1151 PM CDT Wed Jun 29 2016 Scattered showers are currently moving through far western Kansas but are expected to stay west of the GCK terminal. I did place VCTS in the TAFs to account for the close proximity. Otherwise, VFR conditions will prevail with increasing mid level clouds. Winds will generally be from the south to southeast at less than 10 knots. A better chance of thunderstorms are possible tomorrow night, especially around the HYS terminal. && .PRELIMINARY POINT TEMPS/POPS... DDC 89 65 84 65 / 40 60 50 50 GCK 88 65 83 64 / 40 50 50 50 EHA 90 63 87 66 / 40 50 40 40 LBL 91 65 89 68 / 40 50 40 40 HYS 86 64 79 63 / 40 60 60 60 P28 91 68 87 68 / 40 70 50 50 && .DDC Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Hovorka_42 LONG TERM...Kruse AVIATION...Hovorka_42
Area Forecast Discussion National Weather Service Goodland KS 1127 PM MDT WED JUN 29 2016 .UPDATE... Issued at 1122 PM MDT Wed Jun 29 2016 With the storm activity moving south of the area have cancelled the severe thunderstorm watch. North of the Tri-State Area a new round of storms will impact the area during the overnight hours. The storm activity may last into the early morning hours if the storms in the Nebraska Panhandle make it this far south. Main threat with the storms overnight will be large hail although severe wind gusts cannot be ruled out. && .SHORT TERM...(This evening through Thursday) Issued at 157 PM MDT Wed Jun 29 2016 As of 3 PM CDT/2 PM MDT, skies across the Tri-State Region are mostly clear. A few cumulus clouds have recently developed over east Colorado and extreme northwest Kansas. Temperatures are in the mid to upper 80s for most locations. Winds are generally less than 10 mph for most locations. However, south winds are beginning to pick up to 10-15 mph, gusting to 20 mph. At the surface, an area of low pressure was located along the Colorado Front Range. A weak front/remnant outflow boundary is located across eastern Colorado. Aloft, a shortwave trough is moving across Colorado. Thunderstorms have developed over the Rockies ahead of this trough. For this evening and tonight, am expecting another round of strong to severe thunderstorms to move across the region. High resolution guidance, while varying somewhat amongst each piece of guidance, suggest that storms develop this afternoon over eastern Colorado and Wyoming. Then, as the evening progresses, storms should coalesce into another complex or two, spreading southeast across the Tri- State Region. Storms should exit the region after midnight. Overall, am not anticipating quite the storm intensity as last night as the atmosphere has been worked over some. Current mesoanalysis does indicate SBCAPE up to 2500 J/KG in some locations but a cap persists. When the cap breaks, strong/severe thunderstorms should quickly develop. In addition, strong shear remains (0-6 KM Bulk Shear is 40-50 kts). Therefore, anticipating the primary threat with these storms to be damaging winds once again. Any initial development will be capable of large hail, very large possible. Further, recent heavy rains have saturated the soils for some locations. These locations, if they receive additional heavy rain from thunderstorms, would be prone to flash flooding tonight. Was not confident enough to issue a flash flood watch at this time due to some disagreement in guidance with regards to the movement of this complex. For tomorrow, a cold front should push south across the region. As a result of the front and likely extensive cloud cover, cooler temperatures are forecast. Instability parameters remain favorable for some strong/severe thunderstorms, particularly later in the afternoon hours. Thinking the highest chances for thunderstorms (in the afternoon) will be along/west of a line from Benkelman, Nebraska to Tribune, Kansas. Large hail and damaging winds will be possible. Winds aloft should weaken so slower storm movement appears likely. In addition, precipitable water content increases. Therefore, heavy rain and flash flooding may become an issue. .LONG TERM...(Thursday night through Wednesday) Issued at 303 PM MDT Wed Jun 29 2016 Forecast issues will continue to be the threat of thunderstorms, severe weather, and heavy rainfall...especially into the beginning of the weekend. Satellite showing showing an amplified pattern from the eastern Pacific into North America. Upper ridge is currently near the four corners region with subtropical working its way around western side of this ridge. At mid levels...The Canadian/Gfs/Ecmwf were doing the best with the Nam and Sref starting out the worst. The Canadian and gfs did the best on the low level thermal field. Thursday night...numerous shortwave troughs shown. Models appear to not show a lot of lift until the later half of the night when a stronger and negatively tilted shortwave trough approaches the area. Initially most of the precipitation looks to be in the southwest half with a gradual increase in the last half of the night. Some severe possible with probably a greater threat for heavy rainfall due to above normal Pwats. Friday/Friday night...Negatively tilted mid/upper level trough will move slowly toward the area during the day with two different shortwave troughs moving through. One will be early and is the one that begins to affect the area late Thursday night and will move northeast through the day. A second shortwave trough moves in from the southwest in the afternoon. The lift is actually the strongest during the night, with the highest pops of this period, as the entire upper trough moves in closer to the area. Right rear quadrant of jet moves across during the afternoon and evening. There may be a brief break somewhere in their during the day however that will be hard to time. Will have high chance to likely pops in during the day and likely during the night. It may be more embedded thunderstorms in the showers in the morning with more instability and thunderstorms present in the afternoon and night. With a cooler air mass and lots of cloud cover, instability will not be very high. Could not rule out an isolated severe storm but do not expect widespread severe weather. The main threat will be heavy rainfall. Pwats remain near or a little above 1.5 through the entire period which is near 2 standard deviations above normal. Storm motions increase through the day but heavy rainfall still appears to be another good bet. Looks like temperatures will have a hard time climbing this day with cloud cover, ongoing rainfall, and low level upslope. Saturday...the day starts with a complex mid level trough over the forecast area. It appears it slowly moves across the area and then stalls/deepens on top of our area as another shortwave trough comes down the west side of the trough. The models appear to start to try to close off a circulation at 700 mb. Also it appears that a front is near to just southeast of the area. Pwats actually increase into the 1.5 to 2 inch range. It appears that heavy rainfall will be the main threat. However, with a mid level center parked over the area, it could set the stage for low top supercells and landspouts. Saturday night through Wednesday...Continued active period looks to continue. In general the models are the same with the mid level ridge getting suppressed much further south and weak troughing along the west coast of North America. Numerous shortwave troughs are embedded within this flow as one would expect the models are having trouble handling them and do differ on the details of speed and amplitude. Models/Wpc manual progs show synoptic boundaries in and near the area through the whole period. However, given the flow pattern and shortwave troughs aloft, models will probably handle these well at this distance. And that is not even accounting for the mesoscale affects of repeated bouts of thunderstorms. The extended blend provided higher pops on saturday night then steadily decreases pops and has only spotty slight chance to low chance pops for the rest of the period. This looks reasonable considering the model differences and uncertainties in such a complex pattern. However, definitely will be possible for pops to end up being higher. Warmer trend looks to be store, and also appears to be reasonable. && .AVIATION...(For the 06Z TAFS through 06Z Thursday night) Issued at 1122 PM MDT Wed Jun 29 2016 VFR conditions expected for the TAFs. Main issue in the near term will be the line of storms that recently formed north of KMCK. This line of storms will impact the site around 630z and may linger over the site for an hour. Am expecting breezy winds and moderate to possibly heavy rainfall with some hail. During the late afternoon storm activity approaching from the northwest may impact the TAF sites, particularly KGLD. && .GLD Watches/Warnings/Advisories... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...JTL SHORT TERM...RRH LONG TERM...BULLER AVIATION...JTL
Area Forecast Discussion National Weather Service Dodge City KS 1156 PM CDT WED JUN 29 2016 ...Updated aviation section... .UPDATE... Issued at 814 PM CDT Wed Jun 29 2016 Based on radar trends in eastern Colorado and the latest HRRR solutions, increased thunderstorm coverage across the western zones toward midnight. HRRR has a good handle on storm coverage at present, and suggests likely coverage mainly west of Garden City. Per coordination with SPC, strongest risk for damaging winds will be across Hamilton/Kearny county vicinity toward midnight. && .SHORT TERM...(This evening through Thursday) Issued at 251 PM CDT Wed Jun 29 2016 A wind shift line has moved to between Garden City and Dodge City this afternoon with some cumulus just south of Dodge City, and another area of more enhanced cumulus in parts of Barber County. Forecast soundings are unstable with only a weak cap over the Dodge City area and 2000 to 3000 J/kg forecast CAPE. There could be an isolated thunderstorm near the wind shift line and then a slightly better chance in the Barber County area. If any storm develops it could go briefly severe with quarter hail and a strong wind gust. Then later tonight, models show the best chances for rainfall are mainly north of Dodge City, however with this current northwest flow pattern, any storms that develop in eastern Colorado and Nebraska could dive southward into much of the area. Will keep 30 to 50 percent chance going. Severe storms do not look likely with the main threat of strong outflow winds, small hail, and heavy rainfall with any storm complex that can develop. It may also be more difficult for storms to form in far western Kansas this evening and overnight as 700 mb temps are fairly warm around 15C. Lows tonight will range from the mid to upper 60s with light southeast winds. For Thursday, a stronger shortwave in northwest flow aloft is forecast for the afternoon and evening with an attendant cold front moving across western Kansas. Will keep fairly high chances for rainfall going, again with a potential of heavy rainfall. Could also have a chance of strong to severe storms with stronger wind shear forecast. .LONG TERM...(Thursday night through Wednesday) Issued at 305 PM CDT Wed Jun 29 2016 For the period of Thursday night into next Wednesday, an ongoing convective complex of storms may be moving across parts of western Kansas Thursday night with aggravated northwest flow aloft. For Friday northwest flow aloft begins to transition to more zonal flow with more shortwaves forecast into Sunday across the Western High Plains. Will keep fairly high chances going for rainfall, and areas of heavy rainfall still look good. After Sunday, rainfall chances decrease as the main upper jet and any shortwaves move north. Highs will be cooler and in the 80s into Sunday, but then warm back into the 90s by mid week next week. Lows will be mainly in the 60s then warm to around 70 after Monday. && .AVIATION...(For the 06Z TAFS through 06Z Thursday night) Issued at 1151 PM CDT Wed Jun 29 2016 Scattered showers are currently moving through far western Kansas but are expected to stay west of the GCK terminal. I did place VCTS in the TAFs to account for the close proximity. Otherwise, VFR conditions will prevail with increasing mid level clouds. Winds will generally be from the south to southeast at less than 10 knots. A better chance of thunderstorms are possible tomorrow night, especially around the HYS terminal. && .PRELIMINARY POINT TEMPS/POPS... DDC 68 89 65 82 / 30 50 60 50 GCK 66 88 65 83 / 70 50 60 50 EHA 66 91 64 86 / 30 50 60 50 LBL 67 92 66 87 / 40 50 60 50 HYS 67 85 64 81 / 40 40 40 50 P28 70 91 68 84 / 30 50 60 50 && .DDC Watches/Warnings/Advisories... NONE. && $$ UPDATE...Turner SHORT TERM...Kruse LONG TERM...Kruse AVIATION...Hovorka_42
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
1152 PM CDT WED JUN 29 2016 ...Update to aviation forecast discussion... .SHORT TERM...(This Evening through Thursday) Issued at 301 PM CDT WED JUN 29 2016 Current WV imagery at 20Z suggests a remnant MCV continues to slowly drift east across northeastern KS just south of the Nebraska border. MLCAPE values have reached 2500-3000 J/kg per meso analysis and with an upper level shortwave crossing the area, 0-6km shear values are around 30kts. This has provided enough support for at least a couple stronger clusters of thunderstorms over the area. All this activity is slowly moving east and should exit the area by around 5- 6pm this evening. Another shortwave moving through northwest flow aloft should arrive early Thursday morning as it is currently over western portions of the Northern Plains. Although this is not a slam dunk forecast, there are some indications that as the aforementioned shortwave may make its way into the area and provide additional support for some nocturnal storms expected to develop over western IA into far eastern NE and move into eastern portions of the forecast area late tonight after midnight. Additional complex currently developing over western South Dakota may have enough support via an axis of instability setting up into central Kansas as the LLJ veers overnight. These two areas may end up merging in the early morning hours on Thursday and provide a focus for morning storms mainly south of I-70. Depending on how any outflows set up and linger throughout the day will determine where afternoon convection will once again enter the forecast. Expecting this activity will be off over the southern portions of the forecast area as of now. Due to the low confidence in the activity developing and moving in from Western IA, have gone with slight chance POPs overnight and any expected severe activity would likely be in the form of some stronger wind gusts and hail. Temps once again will depend on remnant cloud cover, but expecting high temps tomorrow to reach into the mid 80s. Overnight temps tonight should only dip into the upper 60s and lower 70s with no significant airmass changes but locally impacted by any overnight cold pools. .LONG TERM...(Thursday Night through Wednesday) Issued at 301 PM CDT WED JUN 29 2016 Thunderstorms expected to fire again Thursday afternoon and evening across northwest KS and southwest NE and propagate southeastward in northwest flow aloft. Given source region of expected development, would expect southwest portion of forecast area to have the best chance for overnight precipitation, with lesser possibilities in far northeast KS. Redevelopment north of boundary in warm advection pattern should occur on Friday afternoon with once again best chances across southwest forecast area. As boundary lifts to the north Friday night associated with development of surface low near the CO/OK border, more organized convective complex is expected. Dewpoints in the upper 60s to around 70, PWs between 1.5 and 2 inches and continued positive theta-e advection up over boundary could lead to a round of heavy precipitation, that could continue into Saturday morning in the northeast. Boundary hangs around in central or southern KS Saturday afternoon, depending on which model you look at. Redevelopment of thunderstorms Saturday afternoon seems likely, but location of that development, and best chances hard to pin down this far in advance. Boundary remains in the area Saturday night into Sunday evening with a relatively well-defined shortwave trough moving across the Central Plains in nearly zonal flow aloft. Thus, thunderstorm chances continue through at least Sunday evening, with locally heavy rainfall in some areas. Flooding chances will have to be watched with several periods of thunderstorms over the weekend. After Sunday evening, smaller chances for isolated thunderstorms exist through early next week. Temperatures from Friday through Sunday will be mild for this time of year with plenty of cloud cover and areas of precipitation, with highs only in the upper 70s to lower 80s expected. From Monday through Wednesday of next week, temperatures should warm and heights rise aloft and more sunshine is expected. && .AVIATION...(For the 06Z TAFS through 06Z Thursday Night) Issued at 1152 PM CDT WED JUN 29 2016 VFR conditions are expected through the period. Thunderstorms across Nebraska are expected to move to the southeast through 12Z. Confidence in timing at the terminals is low, and most short term models weaken the complex or keep it to the west of MHK. Will leave out of the tafs for now. Development of additional tsra is possible after 00Z Friday and may affect the MHK terminal after 03Z. Winds light and variable becoming light north to northeast after 18Z. && .TOP Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Drake LONG TERM...GDP AVIATION...53
Area Forecast Discussion National Weather Service Wichita KS 946 PM CDT WED JUN 29 2016 .SHORT TERM...(This evening through Saturday night) Issued at 329 PM CDT Wed Jun 29 2016 Active pattern setting up late this week through the weekend, with periodic episodes of thunderstorms expected across the region, with an accompanying risk of strong/severe storms and locally heavy rain/flooding. Forecast confidence regarding specific details is low for a pattern like this, so focused mainly on trends, and in some cases made little changes from previous forecaster. Current thunderstorm activity over northeast KS is likely being aided by a weak mid-level disturbance along the eastern fringe of warmer 850-700mb temperatures, amidst an unstable airmass. Expecting brunt of this activity to remain just northeast/east of the forecast area this afternoon/evening, although locations generally east of the Flint Hills could get clipped. Otherwise, despite an increasingly unstable airmass, thinking lack of focus will prevent widespread thunderstorm activity across the remainder of the area this afternoon/evening. Like last night, expecting another complex or two of storms to get going across the high plains of CO/NE/KS this evening and propagate southeast overnight. Low confidence on track, longevity or strength of this activity, although like last night anticipate brunt will remain west of the forecast area within zone of more favorable moisture transport. Another area of convection could initiate overnight across northeast KS along eastern fringe of warmer 850-700mb temperatures. If this latter scenario occurs storm motion would bring this activity into eastern/east- central/southeast KS toward morning, but once again confidence is low. As previous forecast mentioned, the threat for widespread storms and associated potential for flooding and severe weather increase Thursday evening and persist through Saturday night. The first round is expected Thursday afternoon and night across the forecast area, as a strong northern CONUS shortwave drives a cold frontal zone south and stalls it across the KS region. Numerous thunderstorms are probable in the vicinity of this frontal zone, some of which will be strong/severe and produce locally very heavy rain. Thinking the highest probability for this scenario will be over southern KS/northern OK. The second round of numerous/widespread thunderstorms is expected Friday night, as moisture transport and isentropic ascent ramp up in response to the frontal zone lifting back north, ahead of shortwave energy approaching from the west. Signal is strongest over generally the northern 2/3 of KS. Once again, locally very heavy rainfall and strong/severe storms are possible. The final round of widespread convection should be Saturday afternoon/night, as the frontal zone passes back east across the forecast area ahead of shortwave energy approaching from the west. Signal for widespread very heavy rainfall is strongest along/north of the front over mainly north-central/northeast KS. Strong/severe storms will once again be possible as well. .LONG TERM...(Sunday through Wednesday) Issued at 329 PM CDT Wed Jun 29 2016 Thunderstorm chances will linger Sunday over mainly southeast KS along/ahead of the cold frontal zone. Other than low probabilities of hit-or-miss storms, the region finally dries out and heats up early to mid next week. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 942 PM CDT Wed Jun 29 2016 Thunderstorms will continue to move eastward from western Kansas and southward across Nebraska tonight, however the activity is expected to decrease as it approaches central Kansas late tonight. Winds will remain light during the day on Thursday and back to the east/southeast direction later in the afternoon. More numerous thunderstorms will develop over western Kansas Thursday afternoon/evening and spread into central Kansas. && .PRELIMINARY POINT TEMPS/POPS... Wichita-KICT 71 89 68 82 / 20 50 60 50 Hutchinson 70 87 66 81 / 30 40 50 50 Newton 69 87 67 81 / 20 50 50 50 ElDorado 70 87 68 81 / 20 50 60 50 Winfield-KWLD 71 89 69 84 / 20 50 70 50 Russell 68 85 64 81 / 40 40 40 50 Great Bend 69 85 65 81 / 40 40 50 50 Salina 69 87 65 82 / 30 40 40 50 McPherson 69 87 66 81 / 30 40 50 50 Coffeyville 70 91 70 83 / 20 40 70 50 Chanute 69 87 69 82 / 20 50 60 50 Iola 69 86 68 82 / 30 50 50 50 Parsons-KPPF 69 89 69 83 / 20 50 70 50 && .ICT Watches/Warnings/Advisories... None. && $$ SHORT TERM...ADK LONG TERM...ADK AVIATION...CDJ
Area Forecast Discussion National Weather Service Dodge City KS 814 PM CDT WED JUN 29 2016 .UPDATE... Issued at 814 PM CDT Wed Jun 29 2016 Based on radar trends in eastern Colorado and the latest HRRR solutions, increased thunderstorm coverage across the western zones toward midnight. HRRR has a good handle on storm coverage at present, and suggests likely coverage mainly west of Garden City. Per coordination with SPC, strongest risk for damaging winds will be across Hamilton/Kearny county vicinity toward midnight. && .SHORT TERM...(This evening through Thursday) Issued at 251 PM CDT Wed Jun 29 2016 A wind shift line has moved to between Garden City and Dodge City this afternoon with some cumulus just south of Dodge City, and another area of more enhanced cumulus in parts of Barber County. Forecast soundings are unstable with only a weak cap over the Dodge City area and 2000 to 3000 J/kg forecast CAPE. There could be an isolated thunderstorm near the wind shift line and then a slightly better chance in the Barber County area. If any storm develops it could go briefly severe with quarter hail and a strong wind gust. Then later tonight, models show the best chances for rainfall are mainly north of Dodge City, however with this current northwest flow pattern, any storms that develop in eastern Colorado and Nebraska could dive southward into much of the area. Will keep 30 to 50 percent chance going. Severe storms do not look likely with the main threat of strong outflow winds, small hail, and heavy rainfall with any storm complex that can develop. It may also be more difficult for storms to form in far western Kansas this evening and overnight as 700 mb temps are fairly warm around 15C. Lows tonight will range from the mid to upper 60s with light southeast winds. For Thursday, a stronger shortwave in northwest flow aloft is forecast for the afternoon and evening with an attendant cold front moving across western Kansas. Will keep fairly high chances for rainfall going, again with a potential of heavy rainfall. Could also have a chance of strong to severe storms with stronger wind shear forecast. .LONG TERM...(Thursday night through Wednesday) Issued at 305 PM CDT Wed Jun 29 2016 For the period of Thursday night into next Wednesday, an ongoing convective complex of storms may be moving across parts of western Kansas Thursday night with aggravated northwest flow aloft. For Friday northwest flow aloft begins to transition to more zonal flow with more shortwaves forecast into Sunday across the Western High Plains. Will keep fairly high chances going for rainfall, and areas of heavy rainfall still look good. After Sunday, rainfall chances decrease as the main upper jet and any shortwaves move north. Highs will be cooler and in the 80s into Sunday, but then warm back into the 90s by mid week next week. Lows will be mainly in the 60s then warm to around 70 after Monday. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 600 PM CDT Wed Jun 29 2016 NW flow aloft expected to spread more SHRA/TSRA into SW Kansas again late tonight. HRRR model solution indicates thunderstorm complex over NE Colorado at 23z will move rapidly SE and begin affecting the terminals around midnight. HRRR solution performed well with last night`s convection, so used it again as a first approximation to place convective TEMPO groups in the 00z TAFs. Strong outflow winds to 50 kts will again be the primary concern, with HRRR suggesting impacts to aviation are most likely at GCK. Stronger shortwave in the NW flow arrives Thursday, with NAM model suggesting potentially widespread TSRA after 18z Thursday. Only included VCTS/CB for now, but TEMPOs are likely with future TAF packages for Thursday. && .PRELIMINARY POINT TEMPS/POPS... DDC 68 89 65 82 / 30 50 60 50 GCK 67 88 65 83 / 40 50 60 50 EHA 67 91 64 86 / 30 50 60 50 LBL 68 92 66 87 / 30 50 60 50 HYS 66 85 64 81 / 40 40 40 50 P28 69 91 68 84 / 30 50 60 50 && .DDC Watches/Warnings/Advisories... NONE. && $$ UPDATE...Turner SHORT TERM...Kruse LONG TERM...Kruse AVIATION...Turner Area Forecast Discussion National Weather Service Phoenix AZ 531 AM MST THU JUN 30 2016 .UPDATE...To Aviation Discussion... && .SYNOPSIS... Plentiful monsoonal moisture will bring continued chances for showers and thunderstorms through at least Friday. Due to the increased moisture and cloud cover, high temperatures will fall with some locations dropping below 100 degrees today and 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... A complex situation is ongoing across eastern Arizona and northern Mexico with multiple mesoscale features and broad upper level support. A very weak (but still relevant) upper level jet max is situated across the Baja northward into central Arizona. To the right of this jet is an area of difluence over southern Arizona which continues to aid in shower and thunderstorm develop early this morning. At least three distinct MCVs can be seen within radar imagery between Phoenix and Tucson. An inverted trough or even a weak closed mid level circulation also resides over northern Sonora Mexico. In the near term there remains enough mid level instability, low level foci, and upper level difluence to support persistent shower and thunderstorm development. Hi-res model data overall have been all over the place with what to expect the rest of tonight, but it seems likely enough the current activity will persist for several more hours. Given all this current activity, widespread cloud cover will likely persist through much of the day. Due to the cloud cover, it is difficult to determine whether this afternoon and evening will be extremely active. We start to lose some upper level support as flow aloft becomes less difluent, but the inverted trough over northern Sonora is shown to move into far southeastern Arizona by this evening. Moisture levels will continue to increase through tonight as 1000-700mb mixing ratios increase toward 12 g/kg as the inverted trough inches northward. Very moist mid levels should result in mostly cloudy skies through at least the south-central Arizona deserts and possibly as far west of the Lower Colorado River Valley. This should keep instability levels fairly low. Another inhibiting factor for any stronger thunderstorm activity will be the warming aloft that is forecast and rather weak mid level lapse rates. Taking all these factors into account, this afternoon and evening will still likely see scattered to even numerous showers east of the Colorado River, but overall thunderstorm activity may be dampened due to the lower instability. Tonight into early Friday may continue to be quite active at least across eastern Arizona as the mid level circulation tracks across Tucson by around midnight and then into east-central Arizona by 12Z Friday morning. The weak upper level jet max will also move into central Arizona by 12Z Friday providing additional support. The combination of the mid level circulation and the jet max will likely provide enough for showers and thunderstorms to last through tonight mainly east of Phoenix. During the day Friday, a drying upper level westerly flow overtakes most of Arizona likely scouring out any mid and upper level cloudiness by late morning. Ample low level and sufficient mid level moisture will still be present for Friday afternoon for us to likely see another day of scattered showers and thunderstorms, mainly from Phoenix eastward. There is some doubt to how much activity will be across the lower deserts as a southwesterly steering flow of 10-20kts will keep most high terrain storms off the lower deserts. The drying westerly flow will persist through this weekend into early next week with most lingering lower desert moisture mixing out on Saturday and completely being scoured out on Sunday. We should still see some isolated to scattered high terrain storms on Saturday, but activity will stay confined to areas east of Phoenix. By Monday, 1000-700mb mixing ratios drop to below 8 g/kg which is even likely too low for any high terrain storms. This flow looks to persist through Tuesday and possibly into next Wednesday before the high shifts far enough north into New Mexico to bring a moist southeasterly flow back to our region. Forecast temperatures during the period start out below normal for areas over Arizona through Friday due to the increased moisture and extensive cloud cover. Once the drying takes place this weekend, temperatures will be on the rebound with near normal highs by Sunday. Monday through Wednesday should see temperatures climb to above normal levels, but at this point it does not look like excessive heat will be a big concern. && .AVIATION... South-Central Arizona including KPHX, KIWA, and KSDL: Today feels more like a day that should be in August...not late June. Deep monsoon moisture surface with various embedded disturbances will continue to circulate through south-central AZ, supporting periods of BKN-OVC CIGS generally 8-10kft. Given the significant increase in moisture and some rainfall over the Phoenix area overnight, some lower SCT decks around nearby terrain/foothills cannot be ruled out. The stronger thunderstorm activity ended overnight, with showers and an isolated lightning strike or two possible through midday. Winds should maintain headings with some slight variants off of east through midday. Confidence in the forecast beyond midday degrades significantly. Conceptually, storm activity should be rather diminished today as the atmosphere is well mixed and worked over from last evenings storm activity. Usually a busy aftn/evening/overnight is followed by a less busy aftn/evening the next day. However, any sky clearing and solar heating of the moisture-rich atmosphere could allow for shower/thunder development into the evening again. For now, left the aftn/even rush periods with at least VCSH mention to introduce some mention of weather in the terminal airspace and elevated easterly breezes, potentially from outflow winds from nearby/on-going storms. Southeast California/Southwest Arizona including KIPL and KBLH: South to southeasterly headings to persist for the next 24 hours, with some afternoon gustiness possible for KBLH. SCT to BKN clouds will develop on and off through the day, with thicker clouds possible towards the afternoon and evening hours. Bulk of the thunderstorm activity should stay east of the river and across Arizona again today, but thunderstorm outflow winds and a few pulse thundershowers near KBLH are possible later this afternoon and evening. 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...None. && $$ Visit us on Facebook...Twitter...and at weather.gov/phoenix DISCUSSION...Kuhlman AVIATION...Nolte FIRE WEATHER...Hernandez
  [top] Area Forecast Discussion National Weather Service Tucson AZ 415 AM MST THU JUN 30 2016 .SYNOPSIS...Periods of showers and thunderstorms with locally heavy rainfall will occur through Friday. A gradual drying trend will then begin Saturday and continue into early next week. However, enough moisture will remain for a few showers and thunderstorms east of Tucson Independence Day and Tuesday. Expect below average daytime temperatures through Friday followed by a warming trend early next week. && .DISCUSSION...Scattered to numerous showers and thunderstorms have occurred throughout the night generally from the Tucson metro area westward and northwestward into western Pima County and south-central and southeast Pinal County. Radar imagery during the past hour or so depicted a distinct low level convergence axis from the nrn/central portion of the Tohono O`Odham Nation northeastward into southeast Pinal County. Showers and thunderstorms continue to feed into this area from the southeast, with new precip development ongoing further east into southwest Graham County. KEMX WSR-88D depicted a cyclonic circulation twist representing an MCV centered just west of Tucson at this time. The aforementioned precip area is associated with a Mesoscale Convective Complex as depicted via cold-topped clouds as per IR water vapor imagery during the past several hours. The imagery distinctly depicts diffluence occurring aloft, and the 30/00Z upper air plots confirmed the presence of a diffluent zone across this forecast area in the 500-300 mb layer. Water vapor satellite imagery also depicts a cyclonic circulation system centered south of this forecast area over northern Sonora Mexico. IR satellite imagery depicted warming cloud tops within the past 30 minutes associated with the band of showers/tstms northwest of Tucson. The notion that showers and thunderstorms will slowly decrease in coverage and intensity during the next few hours is based more on satellite/radar trends versus high resolution models which have yielded a myriad of scenarios since late last evening. The combination of ample moisture with precip water values approaching 2.0 inches across western sections, a fairly deep ely/sely flow regime, and the slow northward migration of the cyclonic circulation system south of the area should produce scattered to numerous showers/tstms today. PoPs were increased and tailored this afternoon to have the highest precip chances to occur in an axis from Nogales to Tucson and further north into southeast Pinal County. The main impacts will be locally heavy rainfall producing at least minor flooding, and the potential for brief strong gusty winds. The GFS was more pronounced versus the ECMWF in depicting a vort max to move northward into Cochise County this evening, then continue newd into west-central New Mexico around daybreak Friday. Have noted that the 30/00Z and 30/06Z NAM remained similar versus previous NAM solutions in depicting qpf bulls-eyes over eastern sections tonight. Thus, would not be surprised to see another MCS to develop over this forecast tonight. Various NWP models then depict locales east of Tucson Friday to be the favored areas for any precip of significance. For this forecast package, have continued with scattered to numerous showers/tstms Friday from Tucson eastward, and only isolated to scattered showers/tstms across western Pima County. A gradual decrease in showers/tstms will start Saturday and continue into early next week associated with light wly flow aloft. Thus, isolated to scattered showers/tstms from Tucson eastward Saturday with dry conditions across western Pima County. A slight chance of showers/tstms continues across eastern sections Sunday, then mainly across the White Mountains Independence Day and Tuesday. The drying trend is progged to be short-lived as deeper sly/sely flow returns next Wednesday. Thus, there is a slight chance of showers/tstms Wednesday east-to-south of Tucson with dry conditions elsewhere. Forecast confidence is quite low regarding high temps today, particularly where PoPs are expected to be the highest. The current forecast high temps for today and Friday will generally average about 10-15 degs or so below normal. A warming trend will then occur Saturday into early next week, with daytime temps returning to close to seasonal normals Monday thru Wednesday. && .AVIATION...VALID THRU 31/12Z. Showers and thunderstorms will continue to be scattered to numerous around southern Arizona through the period including in the vicinity of the terminals. Ceilings generally 8-10k ft with multiple cloud layers above. Gusty winds and brief MVFR conditions in heavy rainfall are likely near storms where wind gusts could exceed 45 kts. Otherwise surface winds generally 10 kt or less. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Above average moisture continues to stream into southern Arizona and combined with the instability in place will yield plenty of showers and thunderstorms through Friday night. Stronger or slower moving storms will be heavy rainers with the strongest storms also capable of winds in excess of 50 mph, mainly during the afternoon and evening hours. If in the field be prepared for the potential for running washes that are normally dry. Atmospheric moisture will begin to diminish across the region Saturday through Tuesday resulting in a decrease in the amount of convection and a slight bump up in afternoon temperatures. Its beginning to look like moisture will begin to return to the area Wednesday for a general uptick in convection once again. && .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 Phoenix AZ 329 AM MST THU JUN 30 2016 .SYNOPSIS... Plentiful monsoonal moisture will bring continued chances for showers and thunderstorms through at least Friday. Due to the increased moisture and cloud cover, high temperatures will fall with some locations dropping below 100 degrees today and 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... A complex situation is ongoing across eastern Arizona and northern Mexico with multiple mesoscale features and broad upper level support. A very weak (but still relevant) upper level jet max is situated across the Baja northward into central Arizona. To the right of this jet is an area of difluence over southern Arizona which continues to aid in shower and thunderstorm develop early this morning. At least three distinct MCVs can be seen within radar imagery between Phoenix and Tucson. An inverted trough or even a weak closed mid level circulation also resides over northern Sonora Mexico. In the near term there remains enough mid level instability, low level foci, and upper level difluence to support persistent shower and thunderstorm development. Hi-res model data overall have been all over the place with what to expect the rest of tonight, but it seems likely enough the current activity will persist for several more hours. Given all this current activity, widespread cloud cover will likely persist through much of the day. Due to the cloud cover, it is difficult to determine whether this afternoon and evening will be extremely active. We start to lose some upper level support as flow aloft becomes less difluent, but the inverted trough over northern Sonora is shown to move into far southeastern Arizona by this evening. Moisture levels will continue to increase through tonight as 1000-700mb mixing ratios increase toward 12 g/kg as the inverted trough inches northward. Very moist mid levels should result in mostly cloudy skies through at least the south-central Arizona deserts and possibly as far west of the Lower Colorado River Valley. This should keep instability levels fairly low. Another inhibiting factor for any stronger thunderstorm activity will be the warming aloft that is forecast and rather weak mid level lapse rates. Taking all these factors into account, this afternoon and evening will still likely see scattered to even numerous showers east of the Colorado River, but overall thunderstorm activity may be dampened due to the lower instability. Tonight into early Friday may continue to be quite active at least across eastern Arizona as the mid level circulation tracks across Tucson by around midnight and then into east-central Arizona by 12Z Friday morning. The weak upper level jet max will also move into central Arizona by 12Z Friday providing additional support. The combination of the mid level circulation and the jet max will likely provide enough for showers and thunderstorms to last through tonight mainly east of Phoenix. During the day Friday, a drying upper level westerly flow overtakes most of Arizona likely scouring out any mid and upper level cloudiness by late morning. Ample low level and sufficient mid level moisture will still be present for Friday afternoon for us to likely see another day of scattered showers and thunderstorms, mainly from Phoenix eastward. There is some doubt to how much activity will be across the lower deserts as a southwesterly steering flow of 10-20kts will keep most high terrain storms off the lower deserts. The drying westerly flow will persist through this weekend into early next week with most lingering lower desert moisture mixing out on Saturday and completely being scoured out on Sunday. We should still see some isolated to scattered high terrain storms on Saturday, but activity will stay confined to areas east of Phoenix. By Monday, 1000-700mb mixing ratios drop to below 8 g/kg which is even likely too low for any high terrain storms. This flow looks to persist through Tuesday and possibly into next Wednesday before the high shifts far enough north into New Mexico to bring a moist southeasterly flow back to our region. Forecast temperatures during the period start out below normal for areas over Arizona through Friday due to the increased moisture and extensive cloud cover. Once the drying takes place this weekend, temperatures will be on the rebound with near normal highs by Sunday. Monday through Wednesday should see temperatures climb to above normal levels, but at this point it does not look like excessive heat will be a big concern. && .AVIATION... South-Central Arizona including KPHX, KIWA, and KSDL: Several high resolution models suggest showers re-entering the picture very late tonight and Thursday morning with cigs falling below 8K ft, but yet staying above 6K ft. Regardless of Shra potential, it appears some measure of these cigs are probable with an easterly wind component predominating. 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 20kt while only sct mid/high clouds pass through the area tonight. Somewhat lower scattered clouds will be possible Thursday. 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...None. && $$ Visit us on Facebook...Twitter...and at weather.gov/phoenix DISCUSSION...Kuhlman AVIATION...MO FIRE WEATHER...Hernandez
  [top] Area Forecast Discussion National Weather Service Flagstaff AZ 243 AM MST THU JUN 30 2016 .SYNOPSIS...Expect active monsoon weather through Saturday with good coverage of showers and thunderstorms each day. Starting Sunday a drier westerly flow across Arizona will bring a downturn in activity heading into the first part of next week. && .DISCUSSION...High pressure centered over New Mexico this morning will slowly slide into Texas over the next 24 to 48 hours. The position to the high will allow monsoon moisture to continue streaming into northern Arizona. For today...Almost too much moisture, especially in the mid levels. At least early on clouds are apt to suppress stronger convective activity, perhaps lasting the whole day. Still expect good coverage of showers and storms but generally a lower chance of intense downpours along and east of a line extending from Prescott to the Grand Canyon. West of this line there could be a bit more sunshine with stronger instability developing along with an isolated 1 to 2 inch drencher possible. On Friday...Moisture will remain across northern Arizona. Some models are indicating that the mid levels could dry some for more sunshine with more moisture in the lower levels. If this pans out stronger storms will be more numerous on Friday. Starting Saturday and lasting into next week...A drying and stabilizing west to southwest will develop. Enough moisture will linger on Saturday for another round of scattered showers and storms. In fact, the vertical wind profile suggests a better potential for an isolated storm or two to become severe on Saturday. Beyond Saturday the drying and stabilizing trend will take hold with just a slight chance of showers and thunderstorms each day. && .AVIATION...For the 12Z Package...Scattered -SHRA through the morning hours. Scattered to numerous TSRA developing aft 17Z. Locally heavy rain may produce MVFR/IFR conditions with small hail also possible. Gusty winds in excess of 40 kts possible in the lower terrain of central AZ (south of the Mogollon Rim). Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Scattered to numerous showers and thunderstorms are expected through Friday. Any storms will be capable of producing locally heavy rain, with gusty outflow winds also possible. The increased clouds and showers will keep daytime temperatures below average. Saturday through Monday...Expect the active monsoon pattern to continue through Saturday, followed by a downturn Sunday and Monday as drier westerly flow develops. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC...McCollum AVIATION...MCS For Northern Arizona weather information visit weather.gov/flagstaff
Area Forecast Discussion National Weather Service Flagstaff AZ 936 PM MST WED JUN 29 2016 .SYNOPSIS...Expect an active wet monsoon pattern through Saturday as the position of the high pressure ridge allows deep moisture to move into Arizona from the south. Abundant moisture and convective instability will produce good coverage of showers and thunderstorms each day. A deep trough will move into the western states over the weekend. A drier southwesterly flow across Arizona will bring a down turn in shower and thunderstorm activity heading into the first half of next week. && .DISCUSSION...Numerous showers and thunderstorms developed today across central Arizona along and south of the Mogollon Rim region. Heavy localized rainfall at times required issuance of several small stream flood advisories and a few flash flood warnings. The most significant flash flood report was for a 4 to 5 foot rise of water along the Cedar Creek basin just south of the Cedar Fire burn area on the White Mountains Apache Tribe reservation. An active wet monsoon pattern over the next few days will continue to produce scattered to numerous showers and thunderstorms each afternoon through Saturday. The position of the subtropical ridge will favor deep southeasterly moisture advection. Precipitable Water amounts will hover around 1 inch for the next few days, which favors abundant shower and thunderstorm activity across northern Arizona. The main threats will be lightning, erratic gusty winds at times near heavier shower bands, and the potential for localized flash flooding. Sunday through Wednesday...A mid-latitude trough moving into the western states will bring drier southwesterly flow into Arizona. This drier flow pattern will lower humidity levels and significantly reduce shower and thunderstorm activity. && .AVIATION...For the 06Z Package...Thunderstorm activity has moved into southern Arizona this evening. Showers and Thunderstorms will redevelop on Thursday after 18Z. Locally heavy rain, small hail, and erratic gusty winds are possible with these 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 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...Bohlin AVIATION...Bohlin FIRE WEATHER...JJ For Northern Arizona weather information visit weather.gov/flagstaff
Area Forecast Discussion National Weather Service Flagstaff AZ 936 PM MST WED JUN 29 2016 .SYNOPSIS...Expect an active wet monsoon pattern through Saturday as the position of the high pressure ridge allows deep moisture to move into Arizona from the south. Abundant moisture and convective instability will produce good coverage of showers and thunderstorms each day. A deep trough will move into the western states over the weekend. A drier southwesterly flow across Arizona will bring a down turn in shower and thunderstorm activity heading into the first half of next week. && .DISCUSSION...Numerous showers and thunderstorms developed today across central Arizona along and south of the Mogollon Rim region. Heavy localized rainfall at times required issuance of several small stream flood advisories and a few flash flood warnings. The most significant flash flood report was for a 4 to 5 foot rise of water along the Cedar Creek basin just south of the Cedar Fire burn area on the White Mountains Apache Tribe reservation. An active wet monsoon pattern over the next few days will continue to produce scattered to numerous showers and thunderstorms each afternoon through Saturday. The position of the subtropical ridge will favor deep southeasterly moisture advection. Precipitable Water amounts will hover around 1 inch for the next few days, which favors abundant shower and thunderstorm activity across northern Arizona. The main threats will be lightning, erratic gusty winds at times near heavier shower bands, and the potential for localized flash flooding. Sunday through Wednesday...A mid-latitude trough moving into the western states will bring drier southwesterly flow into Arizona. This drier flow pattern will lower humidity levels and significantly reduce shower and thunderstorm activity. && .AVIATION...For the 06Z Package...Thunderstorm activity has moved into southern Arizona this evening. Showers and Thunderstorms will redevelop on Thursday after 18Z. Locally heavy rain, small hail, and erratic gusty winds are possible with these 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 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...Bohlin AVIATION...Bohlin FIRE WEATHER...JJ For Northern Arizona weather information visit weather.gov/flagstaff
Area Forecast Discussion National Weather Service Tucson AZ 920 PM MST WED JUN 29 2016 .SYNOPSIS...Expect periods of 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 few showers and thunderstorms mainly east of Tucson next Monday and Tuesday. Cooler temperatures will occur, especially Friday, then warmer temperatures will return early next week. && .DISCUSSION...Strong storms this afternoon as strong outflows helped some valley locations take advantage of above average convective potential and moisture for late June. Several examples of wind gusts in excess of 55 mph and 1 inch hail. Due to the nice easterly flow, additional outflows, and some remaining untapped elevated CAPE we will be prone to shower and thunderstorm activity across the area through the early morning hours. Another round of storms is in the offing Thursday. After lingering debris and shower activity, expect the mid level impulse that helped trigger the large MCS immediately to our south to continue to assist thunderstorm development along with strong outflows and very deep moisture. Elevated risk for isolated severe and heavy rainfall Thursday and Friday. We made minor adjustments based on early 00z analysis and model returns, including beefing up coverage for convection over the next 24 hours. Please see the previous discussion below for additional details. && AVIATION...VALID THRU 31/06Z. Showers with isolated thunderstorms will continue to be in the vicinity of terminals overnight, and then again Thursday. Gusty winds and brief MVFR conditions in heavy rainfall are likely near storms. 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. && .PREV DISCUSSION...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. && .TWC WATCHES/WARNINGS/ADVISORIES... None. && $$ Meyer/French Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Area Forecast Discussion National Weather Service Phoenix AZ 850 PM MST WED JUN 29 2016 .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... Scattered storms have been percolating through much of southern and central Arizona this afternoon and early evening tied to rich moisture profiles, adequate instability, and broad synoptic ascent structures. 00Z KTWC sounding sampled excellent 11-12 g/kg boundary layer moisture profiles with total column Pwats above 1.50 inches and MLcape approaching 1500 J/kg. Though the KPSR sounding failed, objective analysis suggests 10-11 g/kg and Mlcape closer to 1000 J/kg, and current radar returns support this analysis. Thus far, lift has been mainly along better outflow boundaries and through orographic ascent, though this may be rapidly changing. Per objective analysis, dynamical fields are improving with a distinct H7 trough passing into central AZ and upper difluence becoming more pronounced. Radar loops reflect this improving convective environment with organized deeper outflow and hints of an MCV propagating through Gila County. This added lift along with colliding outflow boundaries through the Phoenix metro may allow more numerous storms to form mid to late evening. This is already starting to become evident in radar imagery. Made some modest adjustments to pops given current radar trends, and may need to increase values further over the metro while also extending better chance beyond midnight. .PREVIOUS DISCUSSION... /252 PM MST WED JUN 29 2016/ 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: Numerous outflow boundaries will continue to yield frequently shifting winds through the evening and overnight, though eventually storms to the east should allow for a stronger easterly gradient. Still have held the VCTS mention into terminal sites as environment is favorable for storms. Confidence on coverage and specific direct impact to airfields is low. Several high resolution models suggest showers re-entering the picture very late tonight and Thursday morning with cigs falling below 8K ft, but yet staying above 6K ft. Regardless of Shra potential, it appears some measure of these cigs are probable with an easterly wind component predominating. 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 20kt while only sct mid/high clouds pass through the area tonight. Somewhat lower scattered clouds will be possible Thursday. 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...None. && $$ Visit us on Facebook...Twitter...and at weather.gov/phoenix DISCUSSION...MO/AJ/CB AVIATION...MO FIRE WEATHER...Hernandez
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
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
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 Area Forecast Discussion National Weather Service Tucson AZ 325 PM MST THU JUN 30 2016 .SYNOPSIS...Periods of showers and thunderstorms with locally heavy rainfall will occur through Friday. A gradual drying trend will then begin Saturday and continue into early next week. However, enough moisture will remain for a few showers and thunderstorms east of Tucson through Tuesday. Expect below average daytime temperatures through Friday followed by a warming trend early next week. && .DISCUSSION...Numerous showers are occurring across the CWA this afternoon, with a few thunderstorms trying to develop over areas with the greatest clearing/daytime heating. Surface temperatures are 5 to 10 degrees cooler than this time yesterday, not including locations which were (yesterday) dealing with convection. Latest SPC meso analysis is showing little to no capping over the area in conjunction with 500-1500 J/kg MLCAPE and lifted indices of -3 to -5. The atmosphere is more than primed to go up, but it seems like weak mid and low level lapse rates (again, due to our limited heating) have really hampered our convective development this afternoon. That said, would not be surprised to have a repeat of the last two evenings with regard to overnight activity. The 30/18Z GFS continued to depict a vort max exiting the northeast portion of the CWA late tonight, with another area of vorticity pushing through Cochise County into the early morning hours. Thinking the convection currently ongoing in northern Sonora, just south of the Pima County line, could the beginning of another nocturnal MCS. Anvils from this convection are already spilling over into central Pima County, with this trend expected to expand and continue. Not many changes to the forecast in the near term except for a slight increase in QPF`s, as a few of the stronger cells have been producing decent accumulations. Overall though, do believe the higher amounts will be limited to the stronger cells and spots which see multiple rounds of precip this evening. Another round of showers with a few thunderstorms should then occur after midnight into the pre-dawn hours. Tomorrow should be similar to today, again with the amount of clearing in the morning having the biggest impact in overall storm coverage/mode/strength. We will still have plenty of moisture around to kick convection off should the sun peek out long enough, with storms having the potential to produce gusty winds and very heavy rainfall. Thereafter, the 30/12Z GFS/ECMWF seemed slightly drier than previous solutions for this weekend, and PoPs were adjusted slightly to reflect this. It won`t be terribly noticeable at the surface, as dewpoints only drop slightly into the lower 60s and upper 50s on Saturday, with further drying on Sunday. However, our upper levels will really show the change, with much drier westerly flow dominating the region as high pressure breaks down. 30/18Z GFS/NAM solutions bring PWAT down to less than 1.2 inches by 02/18Z, and potentially under 1 inch by 03/12Z. The result will be a gradual decrease in showers/tstorms from west to east into early next week. By Monday and Tuesday, most locations will be dry, with only a slight chance of showers/tstorms across mainly higher elevations adjacent to the NM border and the White Mountains. The drying trend may be short-lived, at least according to the GFS, as deeper moisture tries to make a reappearance mid to late next week. Have adjusted PoPs upward just slightly on Wednesday and Thursday to account for this possibility. Temperatures Friday will generally average about 10-15 degs or so below normal. Warmer temperatures will occur Saturday and Sunday, with daytime highs returning to seasonal normals Monday thru Wednesday. && AVIATION...VALID THRU 02/00Z. Showers and thunderstorms will continue to be scattered around southern Arizona through the period including in the vicinity of the terminals. Ceilings generally 8-10k ft with multiple cloud layers above. Gusty winds and brief MVFR conditions in heavy rainfall are likely near storms where wind gusts could exceed 35 kts. Otherwise surface winds generally 10 kt or less. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Above average moisture continues to stream into southern Arizona and combined with the instability in place will yield plenty of showers and thunderstorms through Friday night. Stronger or slower moving storms will be heavy rainers with the strongest storms also capable of winds in excess of 40 mph, mainly during the afternoon and evening hours. If in the field be prepared for the potential for running washes that are normally dry. Atmospheric moisture will begin to diminish across the region Saturday through Tuesday resulting in a decrease in the amount of convection and a slight bump up in afternoon temperatures. Its beginning to look like moisture will begin to return to the area Wednesday for a general uptick in convection once again. && .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 Flagstaff AZ 308 PM MST THU JUN 30 2016 .SYNOPSIS...Expect active monsoon weather through Saturday with good coverage of showers and thunderstorms each day. Starting Sunday a drier westerly flow across Arizona will bring a significant downturn in activity through the middle of next week. && .DISCUSSION...Cloud cover and moisture has been extensive across northern AZ today...leading to large areas of light to moderate stratiform rain, and only modest thunderstorm development where surface heating has allowed for the instability to be realized. We expect a showers and a few thunderstorms to continue through the late afternoon...diminishing later this evening. Late tonight and Friday...a weak disturbance working its way up from southern AZ will help promote the redevelopment of showers and a few thunderstorms late tonight...especially over eastern Arizona. Weak westerly flow starts to bring drier air into the midlevels on Friday...and this may be enough for more instability and stronger thunderstorm development by Friday afternoon. Starting late Saturday and lasting into next week...drier and more stable westerly flow begins to take hold over northern Arizona. Significant boundary layer moisture will remain over northern Arizona on Saturday - this, combined with greater wind shear, could promote some strong or severe thunderstorm development on Saturday afternoon before the moist air is swept from the area. We`ll have a few isolated storms on Sunday...then fair and warm weather is expected Monday through the middle of next week. The 4th of July looks to be dry and warm for northern Arizona. && .AVIATION...For the 00Z Package...Scattered showers and isolated thunderstorms are expected to continue overnight...most numerous south of a KFLG-KRQE line. Thunderstorms will re-develop Friday afternoon...with gusty outflow winds and MVFR/IFR conditions in the stronger storms. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Scattered to numerous showers and thunderstorms are expected Friday and again on Saturday. Any storms will be capable of locally heavy rain and gusty outflow winds. Storm motion will generally be from the west Friday afternoon through Saturday. Sunday through Tuesday...Only isolated storms are expected on Sunday...with fair weather Monday and Tuesday as dry westerly flow develops across the area. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC...BAK/TC AVIATION...BAK FIRE WEATHER...BAK For Northern Arizona weather information visit weather.gov/flagstaff
  [top] Area Forecast Discussion...CORRECTED National Weather Service Phoenix AZ 304 PM MST THU JUN 30 2016 .SYNOPSIS... Plentiful monsoonal moisture will bring continued chances for showers and thunderstorms through at least Friday. Due to the increased moisture and cloud cover, high temperatures will be below normal - especially over south-central Arizona. 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 through Friday... With the much cooler boundary layer and lingering cloudiness, afternoon temps are anomalously cool and shower activity over south- central AZ has been largely inconsequential so far. However, convection has begun to redevelop over southeast Arizona and over the Rim. A vort max moving slowly northward through southern and central AZ, along with the higher terrain storms, are factors for keeping PoPs relatively high through tonight. Anticipate that intense storms will be quite limited on the lower elevations but any showers that do form will be efficient rainfall producers. So, the ones wind up being strong will be capable of producing localized flash flooding - more so than yesterday. Conversely, with the higher humidities, anticipate storms will be less likely to produce severe downdrafts. Further west, storms have begun to develop over southwest AZ where surface heating has been much better. Storms there will be better able to produce both heavy rain and strong winds (but in a localized fashion). So far, southern Yavapai and Mohave Counties have been fairly quiet. If that trend were to continue, given the northerly orientation to the steering flow, La Paz county and even eastern Riverside might not be as active as they might otherwise be. It`s early yet so will hold on to changes made earlier (including expansion of PoPs to all of our portion of SE CA). Another factor in play is an upper level short wave (axis over southern California and into the Great Basin) with a speed max oriented over western AZ which will help ventilate updrafts. Also as the stronger winds shift eastward overnight, there may be some lift (associated with the right entrance region) coming into play over southern AZ late tonight and Friday morning. Thus, keep fairly high PoPs going during late night and morning hours. During the day Friday, the mid level circulation and upper level short wave weaken as an upstream short wave redevelops near the California coast. A westerly component to the steering flow doesn`t usually bode well for storms over our forecast area but given the above, and lingering moisture, kept PoPs going through the day and evening. Highs over south-central AZ will be below normal - closer to normal further west. Saturday and Sunday... Dry advection will take place over the weekend with westerly flow aloft. Thus PoPs trend down dramatically. By Sunday, only slight chances for our area and confined to higher terrain east of Phoenix. Conversely, temps warm (to normal by Sunday). Monday through Thursday... Things stay dry through Tuesday (with temps slightly above normal) before steering flow becomes more southerly and an increase in moisture takes place Wed and Thu. However, the increase is only enough for mention of slight chances over south-central AZ by Thu. The ECMWF is more enthusiastic about the moisture return but will need to see more model agreement before reintroducing any significant uptrend in PoPs next week. && .AVIATION... South-Central Arizona Including KPHX, KIWA, and KSDL: Early afternoon satellite depicts cloudy to mostly cloudy skies with a few light rain showers in the area. Expect rain showers to continue in the vicinity through the evening. Skies will remain mostly cloudy with mid to high cloud cigs aob 100 to 200 hft. and SE to SW winds near 5 to 10 kts. There is also a chance of thunderstorms this afternoon and evening although the confidence on the exact timing and coverage was too low to include them in the TAFS. Outflows from distant afternoon and evening thunderstorms could possibly produce erratic, or SE to SW, gusty outflow winds of 20 to 35 kts. However, this is much less likely than last night. Southeast California/Southwest Arizona including KIPL and KBLH: Expect mostly clear skies west of the Lower Colorado River Valley with increasing chances of thunderstorms near and east of the Valley - especially over La Paz County. Apart from thunderstorm outflow, surface winds will favor southeasterly. Aviation discussion not updated for amended TAFs. && .FIRE WEATHER... Sunday through Thursday... Increasing high pressure beginning Sunday is expected to usher in a drier hot weather pattern for most of the week. As slightly below normal afternoon high temperatures on Sunday increase to near normal by Tuesday, minimum humidities in the 15 to 25 percent range will dip to the 10 to 20 percent range on Monday before easing back up into the 15 to 25 percent range by Wednesday. Expect breezy southerly to southwesterly winds on Tuesday with gusts to 18 mph to become breezy to windy on Wednesday with gusts up to 28 mph, especially in the the lower Colorado river valley. Expect overnight recoveries to be mostly fair to occasionally good. There is also a slight chance of thunderstorms mainly over the higher elevations of the Tonto Foothills and S. Gila county on Thursday afternoon and evening. && .SPOTTER INFORMATION STATEMENT... Spotters should follow standard procedures. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ Visit us on Facebook...Twitter...and at weather.gov/phoenix DISCUSSION...AJ AVIATION...Sawtelle FIRE WEATHER...Sawtelle
Area Forecast Discussion National Weather Service Phoenix AZ 250 PM MST THU JUN 30 2016 .SYNOPSIS... Plentiful monsoonal moisture will bring continued chances for showers and thunderstorms through at least Friday. Due to the increased moisture and cloud cover, high temperatures will be below normal - especially over south-central Arizona. 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 through Friday... With the much cooler boundary layer and lingering cloudiness, afternoon temps are anomalously cool and shower activity over south- central AZ has been largely inconsequential so far. However, convection has begun to redevelop over southeast Arizona and over the Rim. A vort max moving slowly northward through southern and central AZ, along with the higher terrain storms, are factors for keeping PoPs relatively high through tonight. Anticipate that intense storms will be quite limited on the lower elevations but any showers that do form will be efficient rainfall producers. So, the ones wind up being strong will be capable of producing localized flash flooding - more so than yesterday. Conversely, with the higher humidities, anticipate storms will be less likely to produce severe downdrafts. Further west, storms have begun to develop over southwest AZ where surface heating has been much better. Storms there will be better able to produce both heavy rain and strong winds (but in a localized fashion). So far, southern Yavapai and Mohave Counties have been fairly quiet. If that trend were to continue, given the northerly orientation to the steering flow, La Paz county and even eastern Riverside might not be as active as they might otherwise be. It`s early yet so will hold on to changes made earlier (including expansion of PoPs to all of our portion of SE CA). Another factor in play is an upper level short wave (axis over southern California and into the Great Basin) with a speed max oriented over western AZ which will help ventilate updrafts. Also as the stronger winds shift eastward overnight, there may be some lift (associated with the right entrance region) coming into play over southern AZ late tonight and Friday morning. Thus, keep fairly high PoPs going during late night and morning hours. During the day Friday, the mid level circulation and upper level short wave weaken as an upstream short wave redevelops near the California coast. A westerly component to the steering flow doesn`t usually bode well for storms over our forecast area but given the above, and lingering moisture, kept PoPs going through the day and evening. Highs over south-central AZ will be below normal - closer to normal further west. Saturday and Sunday... Dry advection will take place over the weekend with westerly flow aloft. Thus PoPs trend down dramatically. By Sunday, only slight chances for our area and confined to higher terrain east of Phoenix. Conversely, temps warm (to normal by Sunday). Monday through Thursday... Things stay dry through Tuesday (with temps slightly above normal) before steering flow becomes more southerly and an increase in moisture takes place Wed and Thu. However, the increase is only enough for mention of slight chances over south-central AZ by Thu. The ECMWF is more enthusiastic about the moisture return but will need to see more model agreement before reintroducing any significant uptrend in PoPs next week. && .AVIATION... South-Central Arizona including KPHX, KIWA, and KSDL: Today feels more like a day that should be in August...not late June. Deep monsoon moisture surface with various embedded disturbances will continue to circulate through south-central AZ, supporting periods of BKN-OVC CIGS generally 8-10kft. Given the significant increase in moisture and some rainfall over the Phoenix area overnight, some lower SCT decks around nearby terrain/foothills cannot be ruled out. The stronger thunderstorm activity ended overnight, with showers and an isolated lightning strike or two possible through midday. Winds should maintain headings with some slight variants off of east through midday. Confidence in the forecast beyond midday degrades significantly. Conceptually, storm activity should be rather diminished today as the atmosphere is well mixed and worked over from last evenings storm activity. Usually a busy aftn/evening/overnight is followed by a less busy aftn/evening the next day. However, any sky clearing and solar heating of the moisture-rich atmosphere could allow for shower/thunder development into the evening again. For now, left the aftn/even rush periods with at least VCSH mention to introduce some mention of weather in the terminal airspace and elevated easterly breezes, potentially from outflow winds from nearby/on-going storms. Southeast California/Southwest Arizona including KIPL and KBLH: South to southeasterly headings to persist for the next 24 hours, with some afternoon gustiness possible for KBLH. SCT to BKN clouds will develop on and off through the day, with thicker clouds possible towards the afternoon and evening hours. Bulk of the thunderstorm activity should stay east of the river and across Arizona again today, but thunderstorm outflow winds and a few pulse thundershowers near KBLH are possible later this afternoon and evening. 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...None. && $$ Visit us on Facebook...Twitter...and at weather.gov/phoenix DISCUSSION...AJ AVIATION...Nolte FIRE WEATHER...Hernandez
Area Forecast Discussion National Weather Service Phoenix AZ 250 PM MST THU JUN 30 2016 .SYNOPSIS... Plentiful monsoonal moisture will bring continued chances for showers and thunderstorms through at least Friday. Due to the increased moisture and cloud cover, high temperatures will be below normal - especially over south-central Arizona. 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 through Friday... With the much cooler boundary layer and lingering cloudiness, afternoon temps are anomalously cool and shower activity over south- central AZ has been largely inconsequential so far. However, convection has begun to redevelop over southeast Arizona and over the Rim. A vort max moving slowly northward through southern and central AZ, along with the higher terrain storms, are factors for keeping PoPs relatively high through tonight. Anticipate that intense storms will be quite limited on the lower elevations but any showers that do form will be efficient rainfall producers. So, the ones wind up being strong will be capable of producing localized flash flooding - more so than yesterday. Conversely, with the higher humidities, anticipate storms will be less likely to produce severe downdrafts. Further west, storms have begun to develop over southwest AZ where surface heating has been much better. Storms there will be better able to produce both heavy rain and strong winds (but in a localized fashion). So far, southern Yavapai and Mohave Counties have been fairly quiet. If that trend were to continue, given the northerly orientation to the steering flow, La Paz county and even eastern Riverside might not be as active as they might otherwise be. It`s early yet so will hold on to changes made earlier (including expansion of PoPs to all of our portion of SE CA). Another factor in play is an upper level short wave (axis over southern California and into the Great Basin) with a speed max oriented over western AZ which will help ventilate updrafts. Also as the stronger winds shift eastward overnight, there may be some lift (associated with the right entrance region) coming into play over southern AZ late tonight and Friday morning. Thus, keep fairly high PoPs going during late night and morning hours. During the day Friday, the mid level circulation and upper level short wave weaken as an upstream short wave redevelops near the California coast. A westerly component to the steering flow doesn`t usually bode well for storms over our forecast area but given the above, and lingering moisture, kept PoPs going through the day and evening. Highs over south-central AZ will be below normal - closer to normal further west. Saturday and Sunday... Dry advection will take place over the weekend with westerly flow aloft. Thus PoPs trend down dramatically. By Sunday, only slight chances for our area and confined to higher terrain east of Phoenix. Conversely, temps warm (to normal by Sunday). Monday through Thursday... Things stay dry through Tuesday (with temps slightly above normal) before steering flow becomes more southerly and an increase in moisture takes place Wed and Thu. However, the increase is only enough for mention of slight chances over south-central AZ by Thu. The ECMWF is more enthusiastic about the moisture return but will need to see more model agreement before reintroducing any significant uptrend in PoPs next week. && .AVIATION... South-Central Arizona including KPHX, KIWA, and KSDL: Today feels more like a day that should be in August...not late June. Deep monsoon moisture surface with various embedded disturbances will continue to circulate through south-central AZ, supporting periods of BKN-OVC CIGS generally 8-10kft. Given the significant increase in moisture and some rainfall over the Phoenix area overnight, some lower SCT decks around nearby terrain/foothills cannot be ruled out. The stronger thunderstorm activity ended overnight, with showers and an isolated lightning strike or two possible through midday. Winds should maintain headings with some slight variants off of east through midday. Confidence in the forecast beyond midday degrades significantly. Conceptually, storm activity should be rather diminished today as the atmosphere is well mixed and worked over from last evenings storm activity. Usually a busy aftn/evening/overnight is followed by a less busy aftn/evening the next day. However, any sky clearing and solar heating of the moisture-rich atmosphere could allow for shower/thunder development into the evening again. For now, left the aftn/even rush periods with at least VCSH mention to introduce some mention of weather in the terminal airspace and elevated easterly breezes, potentially from outflow winds from nearby/on-going storms. Southeast California/Southwest Arizona including KIPL and KBLH: South to southeasterly headings to persist for the next 24 hours, with some afternoon gustiness possible for KBLH. SCT to BKN clouds will develop on and off through the day, with thicker clouds possible towards the afternoon and evening hours. Bulk of the thunderstorm activity should stay east of the river and across Arizona again today, but thunderstorm outflow winds and a few pulse thundershowers near KBLH are possible later this afternoon and evening. 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...None. && $$ Visit us on Facebook...Twitter...and at weather.gov/phoenix DISCUSSION...AJ AVIATION...Nolte FIRE WEATHER...Hernandez
Area Forecast Discussion National Weather Service Flagstaff AZ 1037 AM MST THU JUN 30 2016 .SYNOPSIS...Expect active monsoon weather through Saturday with good coverage of showers and thunderstorms each day. Starting Sunday a drier westerly flow across Arizona will bring a downturn in activity heading into the first part of next week. && .DISCUSSION...UPDATE...Two active areas today across northern Arizona, where showers and thunderstorms may be more active with localized heavy rain, and morewide spread coverage. One area, NW Coconino county late morning through early evening, due to a weak area of divergence aloft. 2nd area northern Gila county, SE Coconino county, southern Navajo county, and Southern Apache county as the upper level disturbance over southern AZ and northern Sonora moves NNE this afternoon and overnight. We will be nudging our grids this afternoon and overnight to accommodate both of these areas of potential shower and thunderstorm activity. && .PREV DISCUSSION /243 AM MST/...High pressure centered over New Mexico this morning will slowly slide into Texas over the next 24 to 48 hours. The position to the high will allow monsoon moisture to continue streaming into northern Arizona. For today...Almost too much moisture, especially in the mid levels. At least early on clouds are apt to suppress stronger convective activity, perhaps lasting the whole day. Still expect good coverage of showers and storms but generally a lower chance of intense downpours along and east of a line extending from Prescott to the Grand Canyon. West of this line there could be a bit more sunshine with stronger instability developing along with an isolated 1 to 2 inch drencher possible. On Friday...Moisture will remain across northern Arizona. Some models are indicating that the mid levels could dry some for more sunshine with more moisture in the lower levels. If this pans out stronger storms will be more numerous on Friday. Starting Saturday and lasting into next week...A drying and stabilizing west to southwest will develop. Enough moisture will linger on Saturday for another round of scattered showers and storms. In fact, the vertical wind profile suggests a better potential for an isolated storm or two to become severe on Saturday. Beyond Saturday the drying and stabilizing trend will take hold with just a slight chance of showers and thunderstorms each day. && .AVIATION...For the 18Z Package...Scattered to numerous TSRA will develop early this afternoon...with locally heavy rain and MVFR/IFR conditions with small hail in the stronger storms. Gusty winds in excess of 40 kts possible...especially in the lower terrain. Scattered showers and TSRA are expected to continue overnight. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Scattered to numerous showers and thunderstorms are expected through Friday. Any storms will be capable of producing locally heavy rain, with gusty outflow winds also possible. The increased clouds and showers will keep daytime temperatures below average. Saturday through Monday...Expect the active monsoon pattern to continue through Saturday, followed by a downturn Sunday and Monday as drier westerly flow develops. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC...TC/McCollum AVIATION...BAK FIRE WEATHER...MCS For Northern Arizona weather information visit weather.gov/flagstaff
Area Forecast Discussion National Weather Service Flagstaff AZ 1015 AM MST THU JUN 30 2016 .SYNOPSIS...Expect active monsoon weather through Saturday with good coverage of showers and thunderstorms each day. Starting Sunday a drier westerly flow across Arizona will bring a downturn in activity heading into the first part of next week. && .DISCUSSION...UPDATE...Two areas of activity today across northern Arizona, where showers and thunderstorms may be more active and move wide spread coverage. One area, NW Coconino county late morning through the afternoon and early evening in an area of weak divergence aloft. 2nd area northern Gila, SE Coconino county, southern Navajo county, and Southern Apache county as the upper level disturbance over southern AZ and northern Sonora moves north late this afternoon and overnight. We will be nudging our grids this afternoon and overnight to accommodate both of these areas of potential shower and thunderstorm activity. && .PREV DISCUSSION /243 AM MST/...High pressure centered over New Mexico this morning will slowly slide into Texas over the next 24 to 48 hours. The position to the high will allow monsoon moisture to continue streaming into northern Arizona. For today...Almost too much moisture, especially in the mid levels. At least early on clouds are apt to suppress stronger convective activity, perhaps lasting the whole day. Still expect good coverage of showers and storms but generally a lower chance of intense downpours along and east of a line extending from Prescott to the Grand Canyon. West of this line there could be a bit more sunshine with stronger instability developing along with an isolated 1 to 2 inch drencher possible. On Friday...Moisture will remain across northern Arizona. Some models are indicating that the mid levels could dry some for more sunshine with more moisture in the lower levels. If this pans out stronger storms will be more numerous on Friday. Starting Saturday and lasting into next week...A drying and stabilizing west to southwest will develop. Enough moisture will linger on Saturday for another round of scattered showers and storms. In fact, the vertical wind profile suggests a better potential for an isolated storm or two to become severe on Saturday. Beyond Saturday the drying and stabilizing trend will take hold with just a slight chance of showers and thunderstorms each day. && .AVIATION...For the 18Z Package...Scattered to numerous TSRA will develop early this afternoon...with locally heavy rain and MVFR/IFR conditions with small hail in the stronger storms. Gusty winds in excess of 40 kts possible...especially in the lower terrain. Scattered showers and TSRA are expected to continue overnight. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Scattered to numerous showers and thunderstorms are expected through Friday. Any storms will be capable of producing locally heavy rain, with gusty outflow winds also possible. The increased clouds and showers will keep daytime temperatures below average. Saturday through Monday...Expect the active monsoon pattern to continue through Saturday, followed by a downturn Sunday and Monday as drier westerly flow develops. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC...TC/McCollum AVIATION...BAK FIRE WEATHER...MCS For Northern Arizona weather information visit weather.gov/flagstaff
Area Forecast Discussion National Weather Service Phoenix AZ 943 AM MST THU JUN 30 2016 .SYNOPSIS... Plentiful monsoonal moisture will bring continued chances for showers and thunderstorms through at least Friday. Due to the increased moisture and cloud cover, high temperatures will fall with some locations dropping below 100 degrees today and 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... A variety of cyclonic circulations evident in satellite imagery this morning. Some of these include one centered near Lake Mead, another over southern AZ, and another over southern Baja. These are in between troughing to our west and ridging centered over northwest Mexico and the interior western states. Radar imagery also indicates a circulation (likely an MCV from last night) centered near the Maricopa/Yavapai border. Otherwise, there is a lot of debris cloudiness covering most of AZ and Sonora. Near and west of the Lower Colorado River Valley. The vast majority of radar echoes this morning are weak showers associated with the aforementioned circulations. However, isolated stronger activity has developed over Mohave County where there has been less cloudiness. For our area, anticipating strongest convection to be over southwest AZ (mainly La Paz County) where surface heating will be better and there will be some steering flow advecting storms southwestward from Yavapai/Mohave Counties. Further west, there is good moisture and RAP depicts very high CAPE with decreasing CIN later this afternoon. May need to increase PoPs in these areas. Meanwhile over south-central AZ, thinking shower activity will be isolated to scattered the whole day but with only isolated stronger storms (more likely over higher terrain). However, with such high PWAT values, the showers will be very efficient rain producers. && .PREVIOUS DISCUSSION...Issued 329 am MST/PDT... A complex situation is ongoing across eastern Arizona and northern Mexico with multiple mesoscale features and broad upper level support. A very weak (but still relevant) upper level jet max is situated across the Baja northward into central Arizona. To the right of this jet is an area of difluence over southern Arizona which continues to aid in shower and thunderstorm develop early this morning. At least three distinct MCVs can be seen within radar imagery between Phoenix and Tucson. An inverted trough or even a weak closed mid level circulation also resides over northern Sonora Mexico. In the near term there remains enough mid level instability, low level foci, and upper level difluence to support persistent shower and thunderstorm development. Hi-res model data overall have been all over the place with what to expect the rest of tonight, but it seems likely enough the current activity will persist for several more hours. Given all this current activity, widespread cloud cover will likely persist through much of the day. Due to the cloud cover, it is difficult to determine whether this afternoon and evening will be extremely active. We start to lose some upper level support as flow aloft becomes less difluent, but the inverted trough over northern Sonora is shown to move into far southeastern Arizona by this evening. Moisture levels will continue to increase through tonight as 1000-700mb mixing ratios increase toward 12 g/kg as the inverted trough inches northward. Very moist mid levels should result in mostly cloudy skies through at least the south-central Arizona deserts and possibly as far west of the Lower Colorado River Valley. This should keep instability levels fairly low. Another inhibiting factor for any stronger thunderstorm activity will be the warming aloft that is forecast and rather weak mid level lapse rates. Taking all these factors into account, this afternoon and evening will still likely see scattered to even numerous showers east of the Colorado River, but overall thunderstorm activity may be dampened due to the lower instability. Tonight into early Friday may continue to be quite active at least across eastern Arizona as the mid level circulation tracks across Tucson by around midnight and then into east-central Arizona by 12Z Friday morning. The weak upper level jet max will also move into central Arizona by 12Z Friday providing additional support. The combination of the mid level circulation and the jet max will likely provide enough for showers and thunderstorms to last through tonight mainly east of Phoenix. During the day Friday, a drying upper level westerly flow overtakes most of Arizona likely scouring out any mid and upper level cloudiness by late morning. Ample low level and sufficient mid level moisture will still be present for Friday afternoon for us to likely see another day of scattered showers and thunderstorms, mainly from Phoenix eastward. There is some doubt to how much activity will be across the lower deserts as a southwesterly steering flow of 10-20kts will keep most high terrain storms off the lower deserts. The drying westerly flow will persist through this weekend into early next week with most lingering lower desert moisture mixing out on Saturday and completely being scoured out on Sunday. We should still see some isolated to scattered high terrain storms on Saturday, but activity will stay confined to areas east of Phoenix. By Monday, 1000-700mb mixing ratios drop to below 8 g/kg which is even likely too low for any high terrain storms. This flow looks to persist through Tuesday and possibly into next Wednesday before the high shifts far enough north into New Mexico to bring a moist southeasterly flow back to our region. Forecast temperatures during the period start out below normal for areas over Arizona through Friday due to the increased moisture and extensive cloud cover. Once the drying takes place this weekend, temperatures will be on the rebound with near normal highs by Sunday. Monday through Wednesday should see temperatures climb to above normal levels, but at this point it does not look like excessive heat will be a big concern. && .AVIATION... South-Central Arizona including KPHX, KIWA, and KSDL: Today feels more like a day that should be in August...not late June. Deep monsoon moisture surface with various embedded disturbances will continue to circulate through south-central AZ, supporting periods of BKN-OVC CIGS generally 8-10kft. Given the significant increase in moisture and some rainfall over the Phoenix area overnight, some lower SCT decks around nearby terrain/foothills cannot be ruled out. The stronger thunderstorm activity ended overnight, with showers and an isolated lightning strike or two possible through midday. Winds should maintain headings with some slight variants off of east through midday. Confidence in the forecast beyond midday degrades significantly. Conceptually, storm activity should be rather diminished today as the atmosphere is well mixed and worked over from last evenings storm activity. Usually a busy aftn/evening/overnight is followed by a less busy aftn/evening the next day. However, any sky clearing and solar heating of the moisture-rich atmosphere could allow for shower/thunder development into the evening again. For now, left the aftn/even rush periods with at least VCSH mention to introduce some mention of weather in the terminal airspace and elevated easterly breezes, potentially from outflow winds from nearby/on-going storms. Southeast California/Southwest Arizona including KIPL and KBLH: South to southeasterly headings to persist for the next 24 hours, with some afternoon gustiness possible for KBLH. SCT to BKN clouds will develop on and off through the day, with thicker clouds possible towards the afternoon and evening hours. Bulk of the thunderstorm activity should stay east of the river and across Arizona again today, but thunderstorm outflow winds and a few pulse thundershowers near KBLH are possible later this afternoon and evening. 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...None. && $$ Visit us on Facebook...Twitter...and at weather.gov/phoenix DISCUSSION...AJ PREVIOUS DISCUSSION...Kuhlman AVIATION...Nolte FIRE WEATHER...Hernandez
AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
1100 AM PDT THU JUN 30 2016 ...Aviation discussion updated... .SYNOPSIS... Breezy winds for Santa Barbara...Ventura and Los Angeles mountains and deserts into Friday. The increasing onshore flow into Independence Day will spread the overnight marine layer farther inland and bring a cooling trend. The high should roll back in on Monday for a gradual warmup for next week. The temperatures will remain above normal through the forecast period. && .SHORT TERM...(TDY-SAT) .UPDATE...12z models so far offering up nothing really new to at least the short term portion of the forecast. Cooling trend with a deepening marine lyr the main themes the next few days. There`s a little bit of mid level moisture to our east today but aside from possibly a few afternoon cu over the mtns they shouldn`t amount to anything. Dry southwest flow will keep the area basically cloud free through the weekend with the exception of the night/morning marine lyr, some of which will hang around the beaches through the afternoon. && Overall, 00Z models in good synoptic agreement through the period. At upper levels, ridge will be replaced by a weak trough developing over northern/central California. Near the surface, onshore flow is forecast to gradually strengthen through the period. Forecast-wise, main concern in the short term will be the marine layer stratus as well as temperatures. Current sounding data indicates marine inversion running between 1000 and 1500 feet while satellite shows stratus filling in across the coastal plain. With the weak upper trough and increasing onshore flow, the marine inversion should deepen over the next couple of days with stratus and fog penetrating further inland to the coastal valleys. Each afternoon, the stratus should dissipate nicely as the inversion will likely not be too strong. Other than the marine layer stratus, skies should remain mostly clear through the period. As for temperatures, the increased marine influence as well as lowering thicknesses will lead to a cooling trend through Saturday. The most noticeable cooling will occur today and again on Friday with only minor additional cooling on Saturday. Temperatures on Friday/Saturday will generally be a couple degrees below seasonal normals. As for winds, the increasing onshore flow will likely generate some gusty afternoon/evening southwesterly winds across the mountains and deserts. However, at this time, there does not appear to be any wind that would approach advisory thresholds. .LONG TERM...(SUN-WED) Overall, 00Z models remain on the same synoptic page through the period. At upper levels, trough will disappear as a flat ridge builds in from the east. Near the surface, moderate onshore flow will continue (although slowly weakening from day-to-day). Forecast-wise, nothing too exciting is anticipated into the middle of next week. With the above synoptic pattern, the main issues will continue to be the marine layer stratus and temperatures. There will be some day-to-day variation in the areal coverage of the stratus, but still should be plenty of night/morning stratus in the coastal valleys each day. As for temperatures, there should be a gradual warming trend, especially away from the beaches. At this time, the mid-level flow looks to remain southwesterly which should keep any monsoonal moisture to the east through Wednesday. && .AVIATION...30/18Z... At 17Z at KLAX... The inversion was about 3950 feet deep. The top of the inversion was near 5600 feet with a temperature of about 25 degrees Celsius. Overall... Moderate confidence in the 18z TAFs. The uncertainty is primarily due to the timing of the marine incursion with some uncertainty regarding the location and intensity as well. The marine incursion is lingering a bit in some coastal locations but should be dissipated by late morning. It will return tonight in a similar fashion as to last night though a bit deeper and that will get it into the adjacent coastal valleys sooner and with greater intensity. The deeper incursion will result in a slightly delayed diminishment tomorrow morning but all sites are expected to be VFR by midday. Otherwise and elsewhere VFR conditions will prevail. KLAX... Moderate confidence in the 18z TAF. The uncertainty is primarily due to the timing of the marine incursion with some uncertainty regarding the intensity as well. VFR conditions will prevail into the evening then the marine incursion will return tonight in a similar fashion as to last night though a bit deeper. The deeper incursion will result in a slightly delayed diminishment tomorrow morning but KLAX should be VFR by late morning. KBUR... Moderate confidence in the 18z TAF. The uncertainty is primarily due to the timing of the marine incursion making its way into the San Fernando Valley tonight. The incursion will be deeper tonight so it will return sooner and with more intensity than last night. The deeper incursion will also result in a slightly delayed diminishment tomorrow morning but KBUR will be VFR by late morning. && .MARINE...30/830 AM... Overall... Small Craft Advisory winds will continue across the outer waters through the early morning hours. Steep combined seas of 7 to 10 feet across the outer waters will slowly subside tonight. Winds and seas across all coastal waters will remain below advisory levels from mid morning Friday through the weekend. Patchy dense fog will continue across the coastal waters into at least the weekend. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Beach Hazards Statement in effect through Friday evening For zones 40-41-87. (See LAXCFWLOX). PZ...Small Craft Advisory in effect until 3 AM PDT Friday For zones 670-673-676. (See LAXMWWLOX). && $$ PUBLIC...MW/DB AVIATION...KJ MARINE...KJ SYNOPSIS...Seto weather.gov/losangeles
Area Forecast Discussion National Weather Service San Francisco Bay Area 1039 AM PDT THU JUN 30 2016 .SYNOPSIS...Onshore flow will continue to bring cooler air into far inland valleys through the weekend and into early next week. Temperatures will be near seasonal normals for the Fourth of July Holiday Weekend with seasonal temperatures likely persisting through the middle of next week. && .DISCUSSION...as of 09:10 AM PDT Thursday...The marine layer has deepened slightly overnight and resulted in stratus spreading well inland this morning, especially into the Salinas Valley. Meanwhile, drier air in the boundary layer continues to advect southward and has allowed cloud cover to burn-off rapidly this morning across the North Bay and over the northern offshore waters. Do expect the cloud cover to burn-off inland through the morning and give way to mostly sunny conditions. Daytime temperatures near the coast will greatly depend on if/when cloud cover clears along the coast. Upper 50s to lower 60s will be common near the coast with widespread 70s and 80s inland. However, do expect some 90s in the hills and far interior valleys again this afternoon. Have made a few adjustments to the sky cover to reflect current trends. Otherwise, the ongoing forecast remains on track for today with no major updates needed. && .PREV DISCUSSION...As of 2:52 AM PDT Thursday...The Fort Ord Profiler indicates a marine layer depth of around 1500 feet, and the latest satellite fog product imagery shows coastal stratus from the Golden Gate south, and also extending locally into the San Francisco Bay area and well into the Monterey Bay area and into the entire Salinas Valley. Temperatures are running steady compared to yesterday morning at this time with readings in the mid to upper 50s at most area airports. The onshore surface pressure gradients are still moderate to strong with 2.9 mb between SFO and SAC and 5.7 from SFO to LAS. High pressure aloft is weakening as an upper level trough settles in over the western states. This factor combined with the continued onshore flow will allow cooler air to filter inland. This will result in cooler temperatures through the weekend, and also persisting into next week as the trough deepens somewhat. High temperatures early next week are forecast to be at or below seasonal normals...upper 50s and 60s at the coast, to the 70s and 80s around the Bay, to the mid 90s well inland. Aside from occasional night and morning coastal fog/drizzle, conditions will be dry through the period. && .AVIATION...as of 10:33 AM PDT Thursday...With the exception of Monterey Bay terminals, VFR conditions prevail. Expect a very slow clearing for KMRY through this afternoon. Clouds linger along the coast through the day so an early return seems likely. IFR to MVFR Cigs tonight. Vicinity of KSFO...VRF through this evening. Cigs return after 06z and remain through the Friday AM rush. Gusty W to NW will be possible this afternoon. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...IFR cigs linger for KMRY with clearing on the doorstep of KSNS. Cigs return early this evening. && .MARINE...as of 10:32 AM PDT Thursday...High pressure over the eastern pacific will keep gusty north winds over the coastal waters. Winds will be strongest over the outer waters resulting in hazardous conditions. High pressure will weaken thursday evening bringing lighter winds to the inner coastal waters and improving sea conditions for the weekend. && .MTR WATCHES/WARNINGS/ADVISORIES... .Tday...SCA...Pt Arena to Pigeon Pt 10-60 nm SCA...Pt Arena to Pt Reyes 0-10 nm SCA...SF Bay from 12 PM SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm && $$ PUBLIC FORECAST: RGass AVIATION: MM MARINE: MM 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 943 AM MST THU JUN 30 2016 .SYNOPSIS... Plentiful monsoonal moisture will bring continued chances for showers and thunderstorms through at least Friday. Due to the increased moisture and cloud cover, high temperatures will fall with some locations dropping below 100 degrees today and 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... A variety of cyclonic circulations evident in satellite imagery this morning. Some of these include one centered near Lake Mead, another over southern AZ, and another over southern Baja. These are in between troughing to our west and ridging centered over northwest Mexico and the interior western states. Radar imagery also indicates a circulation (likely an MCV from last night) centered near the Maricopa/Yavapai border. Otherwise, there is a lot of debris cloudiness covering most of AZ and Sonora. Near and west of the Lower Colorado River Valley. The vast majority of radar echoes this morning are weak showers associated with the aforementioned circulations. However, isolated stronger activity has developed over Mohave County where there has been less cloudiness. For our area, anticipating strongest convection to be over southwest AZ (mainly La Paz County) where surface heating will be better and there will be some steering flow advecting storms southwestward from Yavapai/Mohave Counties. Further west, there is good moisture and RAP depicts very high CAPE with decreasing CIN later this afternoon. May need to increase PoPs in these areas. Meanwhile over south-central AZ, thinking shower activity will be isolated to scattered the whole day but with only isolated stronger storms (more likely over higher terrain). However, with such high PWAT values, the showers will be very efficient rain producers. && .PREVIOUS DISCUSSION...Issued 329 am MST/PDT... A complex situation is ongoing across eastern Arizona and northern Mexico with multiple mesoscale features and broad upper level support. A very weak (but still relevant) upper level jet max is situated across the Baja northward into central Arizona. To the right of this jet is an area of difluence over southern Arizona which continues to aid in shower and thunderstorm develop early this morning. At least three distinct MCVs can be seen within radar imagery between Phoenix and Tucson. An inverted trough or even a weak closed mid level circulation also resides over northern Sonora Mexico. In the near term there remains enough mid level instability, low level foci, and upper level difluence to support persistent shower and thunderstorm development. Hi-res model data overall have been all over the place with what to expect the rest of tonight, but it seems likely enough the current activity will persist for several more hours. Given all this current activity, widespread cloud cover will likely persist through much of the day. Due to the cloud cover, it is difficult to determine whether this afternoon and evening will be extremely active. We start to lose some upper level support as flow aloft becomes less difluent, but the inverted trough over northern Sonora is shown to move into far southeastern Arizona by this evening. Moisture levels will continue to increase through tonight as 1000-700mb mixing ratios increase toward 12 g/kg as the inverted trough inches northward. Very moist mid levels should result in mostly cloudy skies through at least the south-central Arizona deserts and possibly as far west of the Lower Colorado River Valley. This should keep instability levels fairly low. Another inhibiting factor for any stronger thunderstorm activity will be the warming aloft that is forecast and rather weak mid level lapse rates. Taking all these factors into account, this afternoon and evening will still likely see scattered to even numerous showers east of the Colorado River, but overall thunderstorm activity may be dampened due to the lower instability. Tonight into early Friday may continue to be quite active at least across eastern Arizona as the mid level circulation tracks across Tucson by around midnight and then into east-central Arizona by 12Z Friday morning. The weak upper level jet max will also move into central Arizona by 12Z Friday providing additional support. The combination of the mid level circulation and the jet max will likely provide enough for showers and thunderstorms to last through tonight mainly east of Phoenix. During the day Friday, a drying upper level westerly flow overtakes most of Arizona likely scouring out any mid and upper level cloudiness by late morning. Ample low level and sufficient mid level moisture will still be present for Friday afternoon for us to likely see another day of scattered showers and thunderstorms, mainly from Phoenix eastward. There is some doubt to how much activity will be across the lower deserts as a southwesterly steering flow of 10-20kts will keep most high terrain storms off the lower deserts. The drying westerly flow will persist through this weekend into early next week with most lingering lower desert moisture mixing out on Saturday and completely being scoured out on Sunday. We should still see some isolated to scattered high terrain storms on Saturday, but activity will stay confined to areas east of Phoenix. By Monday, 1000-700mb mixing ratios drop to below 8 g/kg which is even likely too low for any high terrain storms. This flow looks to persist through Tuesday and possibly into next Wednesday before the high shifts far enough north into New Mexico to bring a moist southeasterly flow back to our region. Forecast temperatures during the period start out below normal for areas over Arizona through Friday due to the increased moisture and extensive cloud cover. Once the drying takes place this weekend, temperatures will be on the rebound with near normal highs by Sunday. Monday through Wednesday should see temperatures climb to above normal levels, but at this point it does not look like excessive heat will be a big concern. && .AVIATION... South-Central Arizona including KPHX, KIWA, and KSDL: Today feels more like a day that should be in August...not late June. Deep monsoon moisture surface with various embedded disturbances will continue to circulate through south-central AZ, supporting periods of BKN-OVC CIGS generally 8-10kft. Given the significant increase in moisture and some rainfall over the Phoenix area overnight, some lower SCT decks around nearby terrain/foothills cannot be ruled out. The stronger thunderstorm activity ended overnight, with showers and an isolated lightning strike or two possible through midday. Winds should maintain headings with some slight variants off of east through midday. Confidence in the forecast beyond midday degrades significantly. Conceptually, storm activity should be rather diminished today as the atmosphere is well mixed and worked over from last evenings storm activity. Usually a busy aftn/evening/overnight is followed by a less busy aftn/evening the next day. However, any sky clearing and solar heating of the moisture-rich atmosphere could allow for shower/thunder development into the evening again. For now, left the aftn/even rush periods with at least VCSH mention to introduce some mention of weather in the terminal airspace and elevated easterly breezes, potentially from outflow winds from nearby/on-going storms. Southeast California/Southwest Arizona including KIPL and KBLH: South to southeasterly headings to persist for the next 24 hours, with some afternoon gustiness possible for KBLH. SCT to BKN clouds will develop on and off through the day, with thicker clouds possible towards the afternoon and evening hours. Bulk of the thunderstorm activity should stay east of the river and across Arizona again today, but thunderstorm outflow winds and a few pulse thundershowers near KBLH are possible later this afternoon and evening. 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...None. && $$ Visit us on Facebook...Twitter...and at weather.gov/phoenix DISCUSSION...AJ PREVIOUS DISCUSSION...Kuhlman AVIATION...Nolte FIRE WEATHER...Hernandez