Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 07/20/16

Area Forecast Discussion
National Weather Service Tucson AZ
902 PM MST TUE JUL 19 2016

.SYNOPSIS...Scattered mainly afternoon and evening showers and
thunderstorms will occur again Wednesday. A decrease in coverage of
showers and thunderstorms will then prevail Thursday into this
weekend. Expect hotter daytime temperatures Thursday through
Saturday followed by a minor moderation in temperatures early next
week.

&&

.DISCUSSION...High pressure resides over the central and southern
plains, with Arizona on the western flank of the ridge, which is
drawing significant moisture northward across the desert southwest.
The 20/00Z KTWC sounding showed a PW of 1.39 inches. In addition,
dewpoints are currently in the upper 50s to the mid 60s.

It was a fairly active day earlier this afternoon and evening with
scattered showers and storms prompting the issuance of several
Significant Weather Advisories as well as a few Severe Thunderstorm
Warnings. Still an ongoing flood advisory through 9:15 PM for
northwest Cochise county, but another Urban and Small Stream Flood
Advisory is in effect through 10:45 pm across southern parts of
Graham county.

Made some adjustments to the short term POP grids to reflect the
ongoing convection and to slowly taper off the activity through the
remainder of the evening and during the overnight hours. Did keep
isolated to low end scattered showers and storms in the forecast
area-wide through the morning hours on Wednesday.

Also made some tweaks to the short term hourly temperature and
dewpoint grids to reflect the most recent trends.

For info beyond tonight, please refer to the previous discussion
below.

&&

.AVIATION...VALID THRU 21/06Z.
Scattered -TSRA/-SHRA this evening followed by isolated -SHRA across
the area late tonight into Wednesday morning. Expect scattered
-TSRA/-SHRA to return Wednesday afternoon. Brief wind gusts to 45
kts and MVFR conditions will occur with stronger TSRA. Surface wind
will generally be variable in direction less than 12 kts thru the
period. Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...Adequate moisture for scattered afternoon and
evening thunderstorms again Wednesday. A drying trend will then lead
to reduced coverage of showers and thunderstorms Thursday into this
weekend. Moisture will remain adequate for isolated to scattered
thunderstorms early next week. Outside of gusty thunderstorm
outflows, 20-foot winds will be terrain driven and mostly less than
15 mph.

&&

.PREV DISCUSSION...Have continued with scattered mainly
afternoon/evening showers/tstms again Wednesday. The 19/12Z
GFS/ECMWF/CMC were similar versus their respective solutions in
depicting a gradual daily decrease in showers/tstms to begin
Thursday and continue into this weekend. Given the progged easterly
mid-level flow, precip-free conditions area-wide should not occur as
happened earlier this month. However, moisture should remain
sufficient for isolated to scattered afternoon and evening showers
and thunderstorms Thursday through next Tuesday.

A warming trend will occur Wednesday through Friday as heights/
thicknesses increase due to a consolidation of an upper high over
southern California. Expect some minor moderation in daytime temps
early next week, but daytime temps will remain above normal.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...None.

&&

$$

DISCUSSION...Mollere
PREVIOUS DISCUSSION...Francis

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  [top] Area Forecast Discussion National Weather Service Flagstaff AZ 902 PM MST TUE JUL 19 2016 .SYNOPSIS...Monsoon moisture will continue to keep showers and thunderstorms in the forecast through at least Thursday. On Friday, a dry westerly flow will decrease shower coverage across northwestern Arizona with decent chances for thunderstorms hanging around across Navajo and Apache counties. && .DISCUSSION... Though southern Arizona remains active this evening, storm activity has diminished to isolated coverage across northern portions of the state. Short-term forecast reflects this well, with no major updates anticipated in the near future. && .PREV DISCUSSION /410 PM MST/...Wednesday`s weather will continue to be active with heavy showers and thunderstorms across northern Arizona. An upper level low identified in the 200-300 mb streamlines and vorticity pattern may enhance thunderstorm activity in the late afternoon across portions of central Arizona. Extensive cloud cover in the morning across southern Navajo and Apache counties may delay the start of convection into the late afternoon with some activity continuing into the evening hours over portion northeastern Arizona. Thursday and Friday...Deeper moisture will persist across the state with good chances for storm activity. By Friday a drier airmass moving in from the West will start a transition to drier low grade Monsoon activity. This drier air will lower chances for convection in Coconino and Yavapai counties, however higher moisture and instability will linger over eastern Arizona keeping scattered showers and thunderstorms in the forecast. Saturday and Sunday...Only isolated to scattered showers and thunderstorms are forecast through the weekend as a drier airmass settles in across northern Arizona. Precipitable water ranges from a quarter of an inch along the Utah border to around three quarters of an inch along the Mogollon Rim. This drier forecast will not be similar to the extended break in the wet Monsoon during the first half of July. && .AVIATION...For the 06Z package...Isolated storms will continue overnight. Look for sct-nmrs SHRA/TSRA to redevelop between 17z- 02z Wednesday. Brief MVFR/IFR conditions with small hail and gusty winds possible with stronger storms. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Thunderstorms can be expected across the forecast area both Wednesday and Thursday. Storms will generally be moving slowly from south to north. Friday through Sunday...Drier air will start to filter in from the west, which will bring a decrease in thunderstorm activity, especially across the western portion of the state. Minimum RH values will drop back into the teens to the north and west of Flagstaff. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC...KD/Bohlin AVIATION...KD FIRE WEATHER...CLM For Northern Arizona weather information visit weather.gov/flagstaff
Area Forecast Discussion National Weather Service Flagstaff AZ 410 PM MST TUE JUL 19 2016 .SYNOPSIS...Good amounts of Monsoon moisture will continue to keep showers and thunderstorms in the forecast through at least Thursday. The main threat from these storms will be localized flash flooding especially over recent fire scars. On Friday a dry westerly flow will decrease shower coverage across northwestern Arizona with decent chances for thunderstorms hanging around across Navajo and Apache counties. Low grade Monsoon shower activity remains in the forecast through the weekend. && .DISCUSSION...Deeper Monsoon northward has spread across northern Arizona with scattered to numerous showers and thunderstorms that developed starting around 11am today. Several flood advisories and a few flash flood warnings were issued today. Most of the warnings were centered over recent fire scars. Wednesday`s weather will continue to be active with heavy showers and thunderstorms across northern Arizona. An upper level low identified in the 200-300 mb streamlines and vorticity pattern may enhance thunderstorm activity in the late afternoon across portions of central Arizona. Extensive cloud cover in the morning across southern Navajo and Apache counties may delay the start of convection into the late afternoon with some activity continuing into the evening hours over portion northeastern Arizona. Thursday and Friday...Deeper moisture will persist across the state with good chances for storm activity. By Friday a drier airmass moving in from the West will start a transition to drier low grade Monsoon activity. This drier air will lower chances for convection in Coconino and Yavapai counties, however higher moisture and instability will linger over eastern Arizona keeping scattered showers and thunderstorms in the forecast. Saturday and Sunday...Only isolated to scattered showers and thunderstorms are forecast through the weekend as a drier airmass settles in across northern Arizona. Precipitable water ranges from a quarter of an inch along the Utah border to around three quarters of an inch along the Mogollon Rim. This drier forecast will not be similar to the extended break in the wet Monsoon during the first half of July. && .AVIATION...For the 00Z package...Sct SHRA/TSRA continue across much of northern AZ. Storms will trend downward in intensity and coverage after 02Z, but a few showers and isolated storms will continue overnight. Look for sct-nmrs SHRA/TSRA to redevelop between 17z-02z Wednesday. Brief MVFR/IFR conditions with small hail and gusty winds possible with stronger storms. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...More thunderstorms can be expected across the forecast area both Wednesday and Thursday. Storms will generally be moving slowly from south to north. Friday through Sunday...Drier air will start to filter in from the west, which will bring a decrease in thunderstorm activity, especially across the western portion of the state. Minimum RH values will drop back into the teens to the north and west of Flagstaff. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC...Bohlin AVIATION...CLM FIRE WEATHER...CLM For Northern Arizona weather information visit weather.gov/flagstaff
Area Forecast Discussion National Weather Service Tucson AZ 245 PM MST TUE JUL 19 2016 .SYNOPSIS...Scattered mainly afternoon and evening showers and thunderstorms will occur again Wednesday. A decrease in coverage of showers and thunderstorms will then prevail Thursday into this weekend. Expect hotter daytime temperatures Thursday through Saturday followed by a minor moderation in temperatures early next week. && .DISCUSSION...Scattered to numerous showers and thunderstorms were occurring generally across central/eastern Pima County, southern Pinal County and Santa Cruz County at this time. Other isolated showers and thunderstorms were also occurring further east across northern Graham County, and the White Mountains. The ongoing showers/tstms will move mainly northwestward during the next few hours, with the main threat being locally heavy rainfall and brief gusty winds. There is still the potential for blowing dust by this evening along the Interstate 10 corridor northwest of Tucson to Phoenix. Various mesoscale models suggest that showers/tstms will this evening mainly across eastern sections as the ongoing showers/tstms decrease markedly in coverage/intensity. Thus, the official forecast continues with scattered showers/ tstms area-wide this evening followed by a slight chance of showers/tstms late tonight into Wednesday morning. Would not be surprised that precip-free conditions occur across much of the area late tonight as has generally been the case the past few nights. However, there will still be enough moisture to support the aforementioned scenario of a slight chance of showers/tstms. Various mesoscale models depict similar coverage of showers/tstms Wednesday. Have continued with scattered mainly afternoon/evening showers/tstms again Wednesday. The 19/12Z GFS/ECMWF/CMC were similar versus their respective solutions in depicting a gradual daily decrease in showers/tstms to begin Thursday and continue into this weekend. Given the progged easterly mid-level flow, precip-free conditions area-wide should not occur as happened earlier this month. However, moisture should remain sufficient for isolated to scattered afternoon and evening showers and thunderstorms Thursday through next Tuesday. A warming trend will occur Wednesday through Friday as heights/ thicknesses increase due to a consolidation of an upper high over southern California. Expect some minor moderation in daytime temps early next week, but daytime temps will remain above normal. && .AVIATION...VALID THRU 21/00Z. Scattered -TSRA/-SHRA this evening followed by isolated -SHRA across the area late tonight into Wednesday morning. Expect scattered -TSRA/-SHRA to return Wednesday afternoon. Brief wind gusts to 45 kts and MVFR conditions will occur with stronger TSRA. Surface wind will generally be variable in direction less than 12 kts thru the period. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Adequate moisture for scattered afternoon and evening thunderstorms again Wednesday. A drying trend will then lead to reduced coverage of showers and thunderstorms Thursday into this weekend. Moisture will remain adequate for isolated to scattered thunderstorms early next week. Outside of gusty thunderstorm outflows, 20-foot winds will be terrain driven and mostly less than 15 mph. && .TWC WATCHES/WARNINGS/ADVISORIES...None. && $$ Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson Francis
  [top] Area Forecast Discussion National Weather Service Phoenix AZ 218 PM MST TUE JUL 19 2016 .SYNOPSIS... An increase in clouds and humidity can be expected during the next couple of days along with a slight chance of showers and thunderstorms, mainly east of the Lower Colorado River Valley. High temperatures over the central deserts will stay near seasonal normals, with hotter conditions over the western deserts. Storm chances on the lower deserts will be slight, with better chances over the higher terrain and over southeast Arizona. During the latter half of the week, storm chances will dwindle, and temperatures will increase to above normal levels. && .DISCUSSION... Tonight and Wednesday... Regional morning weather balloon soundings continued show a rather healthy amount of monsoon moisture strewn across central and southern AZ. Monsoon moisture is not excessive by any means, but not minimal either. And, boundary layer moisture was healthy enough to result in relatively low afternoon convective trigger temperatures. This afternoon there seemed to be an early start to convection in southeast AZ and over southern Gila County zone 24. Low afternoon convective trigger temperatures will make the lower desert airmass in south central AZ more susceptible to convection produced by convective outflows moving in from southeast AZ, especially with weakness/support aloft. Upper level weakness and support is what we`ve been focusing on for a few days now with the approaching inverted trof (IT) from Chihuahua Mexico. At 2 pm mst the leading edge of this IT feature had moved into the southeast AZ corner, with convection breaking out ahead of its leading edge, and in a weak difluent zone aloft. Various meso-scale models have widely varying spacial and temporal solutions for convection, but the bottom line is most of it is produced in southeast AZ running along a north south line from near Tucson to our southern Gila County Zone 24. Additionally, some models produce a strong convective outflow that spreads northwest toward Pinal and Maricopa Counties, including Phoenix between 7 pm and 10 pm mst. The magnitude of this outflow boundary will likely initiate secondary convection. Therefore the chance of showers and thunderstorms will continue this evening through late night, with a slight chance of lingering showers continuing through early Wednesday morning. Wednesday...Monsoon moisture will be still be entrenched over the region. With mid/upper level disturbances departing the area, this will result in another low grade monsoon forecast Wednesday afternoon and evening. Thursday through Monday...monsoon moisture is forecast to thin a little as drier air from New Mexico and Colorado mix over the area. At the same time atmospheric height and thickness values increase dramatically over the region, and if it weren`t for remnant monsoon moisture, afternoon temperatures would be much higher. Therefore afternoon desert temperatures are forecast to be above the 110 degree mark, but approaching 115 over the driest low humidity area of southeast CA. && .AVIATION... South-Central Arizona Including KPHX, KIWA, and KSDL: Thunderstorms are possible this afternoon with development already occurring over the higher terrain to the north and east of Phoenix. These storms, along with any that develop around the metro, could produce outflow winds that could impact any terminal. Current storm development suggests outflows from the north or the east are more likely but the exact timing and direction of wind shifts is difficult pin down at this time Southeast California/Southwest Arizona including KIPL and KBLH: Little aviation concerns through with storm activity well off to the east into central Arizona. Expect mostly clear skies and southerly winds through the evening and into tomorrow. Aviation Discussion not updated for amended TAFs. && .FIRE WEATHER... Friday through Tuesday...Temperatures will trend back into an above normal range through the weekend as moisture levels thin and humidity values drop. Thunderstorm/wetting rain chances dwindle and become mostly limited to the higher terrain of eastern Arizona by Friday and Saturday. Consequently, afternoon humidity levels will drop into the 10-25 percent range this weekend. Outside of any thunderstorms, winds will be typical with some afternoon gustiness. && .SPOTTER INFORMATION STATEMENT... Spotter activation may be required for this evening. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ Visit us on Facebook...Twitter...and at weather.gov/phoenix DISCUSSION...Vasquez AVIATION...Deemer/Iniguez FIRE WEATHER...Deemer/Iniguez
Area Forecast Discussion National Weather Service Flagstaff AZ 936 AM MST TUE JUL 19 2016 .SYNOPSIS...Monsoon moisture will continue to bring a chance of showers and thundertorms through Thursday. Strong high pressure and drier air could result in a downturn in activity toward the end of the week. && .DISCUSSION...A wet Monsoon weather pattern continues as the subtropical ridge is in a favorable position for northward advection of moisture into Arizona. Expect good coverage for showers and thunderstorms with subtle changes in the location of the heavy rainfall from day to day. The morning forecast grids look good no updates. && .PREV DISCUSSION /242 AM MST/...A wide area of high pressure aloft remained centered over the Oklahoma/Kansas border. The models continue to promise little movement in this high pressure feature over the next few days. The position of the high is placing southerly flow over Arizona with not much change in the moisture profile through Thursday. Moving forward the distribution of showers and thunderstorms will remain very similar to Monday. Isolated heavy rain amounts of an inch or more and localized flooding will be possible. More generally, amounts in the trace to quarter inch category scattered about northern Arizona. From Friday onward...Models show the high pressure system centered over Oklahoma essentially splitting. The western portion of the high will migrate across Arizona and eventually become established over the western United States. If this pattern transpires it will open the door to an influx of drier air from the west. Forecast grids reflect a downturn in monsoon activity but moisture looks too entrenched for a complete shutdown in monsoon activity. We`ll keep you updated. && .AVIATION...For the 18Z package...Primarily VFR conditions are expected for the next 24 hours with bkn cigs aoa 14kft msl. Look for sct-nmrs SHRA/TSRA between 17z-02z, especially over mountain areas. Brief MVFR/IFR conditions and gusty winds possible with stronger storms. Precipitation coverage decreasing after 02z Wed. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Expect another round of thunderstorms over the forecast area today and Wednesday. Storm motion will generally be from the south to north 5-10 mph. Thursday through Saturday...Scattered thunderstorms will persist across the area on Thursday. Drier air filtering into Arizona from the west will bring a decrease in thunderstorm activity on Friday and Saturday...with minimum RH`s dropping back into the teens to the north and west of Flagstaff. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC...Bohlin/McCollum AVIATION...CLM FIRE WEATHER...DL For Northern Arizona weather information visit weather.gov/flagstaff
Area Forecast Discussion National Weather Service Tucson AZ 850 AM MST TUE JUL 19 2016 .SYNOPSIS...Adequate moisture will provide scattered mainly afternoon and evening showers and thunderstorms through Wednesday. A slight decrease in daily coverage of showers and thunderstorms should then occur Thursday into this weekend. Expect near normal daytime temperatures Tuesday followed by a pronounced warming trend later this week. && .DISCUSSION...IR/Visible satellite imagery depicted mostly clear skies to partly cloudy skies at this time. Some of the more prominent cyclonic twists were moving northwestward just east of northern Greenlee County, over northwest Sonora, and over east central Sonora. Water vapor imagery also depicted an inverted trough over southern New Mexico southward into northern Chihuahua Mexico. Ample moisture continues across the area with dewpoints at lower elevations valid 15Z ranging from the mid 50s-mid 60s, and 19/12Z KTWC sounding total precip water value was 1.50 inches. There were some differences between the various mesoscale models regarding the development and evolution of showers/tstms later today. Instead of a model rehash, the official forecast of scattered showers/tstms this afternoon/evening appears to be on track. The main concern this afternoon/evening will be the potential for locally heavy rainfall and brief strong wind gusts that may approach severe thresholds. There is also a potential for blowing dust along the Interstate 10 corridor northwest of Tucson to Phoenix. Forecast confidence is not sufficiently high at this time to issue a Blowing Dust Advisory. A slight chance of showers/tstms continues for much of the area late tonight. High temps this afternoon will generally be a few degs warmer versus Monday. Please refer to the additional sections for further detail. && .AVIATION...VALID THRU 20/18Z. Isolated showers through the early morning hours. Sct-bkn clouds at 6-9k ft agl and bkn-ovc clouds at 10-14k ft agl. Expect scattered showers and thunderstorms this afternoon and evening, then tapering in coverage late tonight. Brief wind gusts of 40-45 kts and MVFR conditions will occur with the stronger TSRA. Outside of gusty outflows, surface wind will generally be less than 12 kts through Wednesday morning. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Ample moisture will ensure daily chances of mainly afternoon and evening showers and thunderstorms this week. A slight decrease in rain chances will occur late in the week into the weekend along with an increase in daytime temperatures. Outside of gusty thunderstorm/outflow winds, expect typical diurnal 20-ft wind patterns each day at mainly less than 15 mph. && .CLIMATE...As the area heats up again, could see a few spots across the western deserts approach record highs later in the week. && .PREV DISCUSSION /250 AM MST/...Isolated light showers were occurring early this morning east of Tucson. Expect these to continue thru sunrise as they move to the WNW. A weak MCV was over SW Graham county as of 2 am, but shouldn`t be a player today as it continue to move NNW. What could be a player later today is the inverted trof currently over Chihuahua MX. This feature is moving slowly to the NW toward the area. Hi-res models focusing best activity W of Tucson, with potential for blowing dust across Pinal county towards Phoenix, and Cochise county. PW values across the remain above normal for July so locally heavy rain a threat. Can`t rule out a severe storm or two. Highs today will be around normal. Scattered afternoon/evening storms Wednesday with highs slightly warmer than today. Starting Thursday and continuing through the upcoming weekend there will be a gradual decrease in shower and thunderstorm activity as sub-tropical ridge expands over the southern CONUS. Still hanging on to enough moisture to keep isolated to scattered storms in the forecast. Highs temperatures will be above normal through this period, maxing out on Friday. && .TWC WATCHES/WARNINGS/ADVISORIES...None. && $$ Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Area Forecast Discussion National Weather Service Phoenix AZ 810 AM MST TUE JUL 19 2016 .SYNOPSIS... An increase in clouds and humidity can be expected during the next couple of days along with a slight chance of showers and thunderstorms, mainly east of the Lower Colorado River Valley. High temperatures over the central deserts will stay near seasonal normals, with hotter conditions over the western deserts. Storm chances on the lower deserts will be slight, with better chances over the higher terrain and over southeast Arizona. During the latter half of the week, storm chances will dwindle, and temperatures will increase to above normal levels. && .DISCUSSION... Regional morning weather balloon soundings continued show a rather healthy amount of monsoon moisture strewn across central and southern AZ. Monsoon moisture is not excessive by any means, but not minimal either. And, boundary layer moisture was healthy enough to result in relatively low afternoon convective trigger temperatures like 102 F in Phoenix, 96 in Tucson, and 88 degrees in Globe/Miami (3-4 thsd msl) in the mountains east of Phoenix. Low afternoon convective trigger temperatures make the lower desert airmass in south central AZ susceptible to convection, easily triggered by numerous convective outflow boundaries running across the lower regions later in the day, especially with weakness/support aloft. Upper level weakness and support is what we`ve been focusing on for a few days now with the approaching inverted trof (IT) from Chihuahua Mexico. Models continue to forecast this IT feature, located just southwest of El Paso in morning water vapor imagery, to move into southeast AZ later this afternoon, then across the greater Phoenix area Wednesday afternoon in a much weakened/washed out state. Numerical guidance continues to put PHX and TUS in a chance shwr/tstm category for later today and tonight due to this approaching IT feature. The chance of showers can possibly continue into the night in south central AZ with all the secondary circulations/outflows it can produce. Due to this approaching feature, the moisture rich boundary layer, and relatively low thermodynamic convective trigger temperatures, we will upgrade the probability of precip into the chance category in south central AZ including Phoenix for tonight. Wednesday`s afternoon and evenings low grade monsoon shwr/tstm possibilities look ok for now. Previous discussion still applies. .Previous Discussion...507 AM MST... Monsoon circulation remains entrenched across Arizona with an impressive plume of deep moisture spreading north from northwest Mexico and running north/northeastward across central and eastern Arizona, around the periphery of a very strong upper high centered over the south-central CONUS. This moist plume is easily seen in the current IR and vapor imagery loops. Steering flow across central/eastern AZ is mostly south to southeast, becoming more southwesterly as you move west and into the far southwest AZ deserts and over SE California. Orientation of this flow will keep most of the convection focused over south-central Arizona this week with very little expected into the SE California deserts. PWAT value at Phoenix from the last 00z raob was healthy at 1.64 inches and there was modest CAPE present in the sounding. 2 am surface dewpoints over the central deserts were elevated, ranging mostly from the upper 50s to middle 60s. Little if any shower activity was noted early this morning on radar, just a fair amount of debris cloudiness spreading north across the lower deserts. Overall, for the next couple of days, we are looking at a low to medium grade monsoon in terms of thunderstorm coverage. Most of the convection will be located over south-central Arizona with slight chances of mainly afternoon and evening storms becoming 30 percent or more over the higher terrain east of Phoenix. Steering flow is not especially strong as the 700-300mb mean winds typically run 10- 15 knots, and most of the disturbances that will rotate around the high and serve as "triggers" for convection are not especially dynamical. Latest vapor imagery loop does show a moderately organized inverted trof spinning over NW Mexico, poised to move into southeast Arizona this morning and across portions of south central and east-central AZ during the day, but it is forecast to weaken as it moves through the area so most of the desert POPs will stay below 25 percent this evening. High temperatures over the central deserts today and Wednesday will stay near seasonal normals due to the elevated humidity, with highs reaching or exceeding 110 over the western deserts where the airmass is drier and there will be more solar insolation. Thursday through Saturday...monsoon moisture is forecast to thin a little as drier air from New Mexico and Colorado mix over the area. At the same time atmospheric height and thickness values increase dramatically over the region, and if it weren`t for remnant monsoon moisture, afternoon temperatures would be much higher. Therefore afternoon desert temperatures are forecast to be above the 110 degree mark, but approaching 115 over the driest low humidity area of southeast CA. We still expect high temperatures to generally stay just below excessive heat warning thresholds during the hottest days such as Friday and Saturday; this is supported by HIL data. By Friday, rain chances in the Phoenix area will struggle to exceed around 10 percent due to the drier air in place. Sunday into Monday...The strong upper high continues to build towards the west, with one high center eventually setting up over central CA. Flow around the high becomes more favorable from the east and monsoon moisture starts to return. As such thunderstorm chances start to rise and we will be seeing lower grade conditions with slight chances for afternoon convection over the lower central deserts, along with 20-30 percent chances across the higher terrain of southern Gila County. Temperatures will trend down slightly as humidity levels rise. && .AVIATION... South-Central Arizona Including KPHX, KIWA, and KSDL: A quiet start to the day with a mix of mid/high clouds moving through and light winds. Thunderstorms are possible again later this afternoon, first developing over the mountains north to east to south of the Phoenix area after 21 UTC. Outflow winds look likely, though hard to discern at this time if they`ll come from the northeast or the southeast (which will impact if any dust comes into play). Seems that some showers will develop later in the evening but low confidence on thunderstorm development/coverage to include in TAFs at this time. Showers could continue into the overnight hours. Southeast California/Southwest Arizona including KIPL and KBLH: Little aviation concerns through into Wednesday morning with few clouds and generally light winds. Aviation Discussion not updated for amended TAFs. && .FIRE WEATHER... Friday through Tuesday... Temperatures will trend back into an above normal range through the weekend as moisture levels thin and humidity values drop. Thunderstorm/wetting rain chances dwindle substantially and become almost exclusively limited to higher terrain of eastern Arizona by Friday/Saturday. Consequently, afternoon humidity levels will drop about ten percent on average, into the 10-25 percent range this weekend. Outside of isolated gusty winds surrounding any thunderstorms, directions will favor an upslope component in the afternoon with gustiness around terrain features and light overnight valley drainage. && .SPOTTER INFORMATION STATEMENT... Spotter activation may be required for this evening. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ Visit us on Facebook...Twitter...and at weather.gov/phoenix DISCUSSION...Vasquez/CB AVIATION...Iniguez FIRE WEATHER...Iniguez/MO
Area Forecast Discussion National Weather Service Phoenix AZ 507 AM MST TUE JUL 19 2016 .SYNOPSIS... An increase in clouds and humidity can be expected during the next couple of days along with a slight chance of showers and thunderstorms, mainly east of the Lower Colorado River Valley. High temperatures over the central deserts will stay near seasonal normals, with hotter conditions over the western deserts. Storm chances on the lower deserts will be slight, with better chances over the higher terrain and over southeast Arizona. During the latter half of the week, storm chances will dwindle, and temperatures will increase to above normal levels. && .DISCUSSION... Monsoon circulation remains entrenched across Arizona with an impressive plume of deep moisture spreading north from northwest Mexico and running north/northeastward across central and eastern Arizona, around the periphery of a very strong upper high centered over the south-central CONUS. This moist plume is easily seen in the current IR and vapor imagery loops. Steering flow across central/eastern AZ is mostly south to southeast, becoming more southwesterly as you move west and into the far southwest AZ deserts and over SE California. Orientation of this flow will keep most of the convection focused over south-central Arizona this week with very little expected into the SE California deserts. PWAT value at Phoenix from the last 00z raob was healthy at 1.64 inches and there was modest CAPE present in the sounding. 2 am surface dewpoints over the central deserts were elevated, ranging mostly from the upper 50s to middle 60s. Little if any shower activity was noted early this morning on radar, just a fair amount of debris cloudiness spreading north across the lower deserts. Overall, for the next couple of days, we are looking at a low to medium grade monsoon in terms of thunderstorm coverage. Most of the convection will be located over south-central Arizona with slight chances of mainly afternoon and evening storms becoming 30 percent or more over the higher terrain east of Phoenix. Steering flow is not especially strong as the 700-300mb mean winds typically run 10- 15 knots, and most of the disturbances that will rotate around the high and serve as "triggers" for convection are not especially dynamical. Latest vapor imagery loop does show a moderately organized inverted trof spinning over NW Mexico, poised to move into southeast Arizona this morning and across portions of south central and east-central AZ during the day, but it is forecast to weaken as it moves through the area so most of the desert POPs will stay below 25 percent this evening. High temperatures over the central deserts today and Wednesday will stay near seasonal normals due to the elevated humidity, with highs reaching or exceeding 110 over the western deserts where the airmass is drier and there will be more solar insolation. Thursday through Saturday...monsoon moisture is forecast to thin a little as drier air from New Mexico and Colorado mix over the area. At the same time atmospheric height and thickness values increase dramatically over the region, and if it weren`t for remnant monsoon moisture, afternoon temperatures would be much higher. Therefore afternoon desert temperatures are forecast to be above the 110 degree mark, but approaching 115 over the driest low humidity area of southeast CA. We still expect high temperatures to generally stay just below excessive heat warning thresholds during the hottest days such as Friday and Saturday; this is supported by HIL data. By Friday, rain chances in the Phoenix area will struggle to exceed around 10 percent due to the drier air in place. Sunday into Monday...The strong upper high continues to build towards the west, with one high center eventually setting up over central CA. Flow around the high becomes more favorable from the east and monsoon moisture starts to return. As such thunderstorm chances start to rise and we will be seeing lower grade conditions with slight chances for afternoon convection over the lower central deserts, along with 20-30 percent chances across the higher terrain of southern Gila County. Temperatures will trend down slightly as humidity levels rise. && .AVIATION... South-Central Arizona Including KPHX, KIWA, and KSDL: A quiet start to the day with a mix of mid/high clouds moving through and light winds. Thunderstorms are possible again later this afternoon, first developing over the mountains north to east to south of the Phoenix area after 21 UTC. Outflow winds look likely, though hard to discern at this time if they`ll come from the northeast or the southeast (which will impact if any dust comes into play). Seems that some showers will develop later in the evening but low confidence on thunderstorm development/coverage to include in TAFs at this time. Showers could continue into the overnight hours. Southeast California/Southwest Arizona including KIPL and KBLH: Little aviation concerns through into Wednesday morning with few clouds and generally light winds. Aviation Discussion not updated for amended TAFs. && .FIRE WEATHER... Friday through Tuesday... Temperatures will trend back into an above normal range through the weekend as moisture levels thin and humidity values drop. Thunderstorm/wetting rain chances dwindle substantially and become almost exclusively limited to higher terrain of eastern Arizona by Friday/Saturday. Consequently, afternoon humidity levels will drop about ten percent on average, into the 10-25 percent range this weekend. Outside of isolated gusty winds surrounding any thunderstorms, directions will favor an upslope component in the afternoon with gustiness around terrain features and light overnight valley drainage. && .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ Visit us on Facebook...Twitter...and at weather.gov/phoenix DISCUSSION...CB AVIATION...Iniguez FIRE WEATHER...Iniguez/MO
Area Forecast Discussion National Weather Service Phoenix AZ 325 AM MST TUE JUL 19 2016 .SYNOPSIS... An increase in clouds and humidity can be expected during the next couple of days along with a slight chance of showers and thunderstorms, mainly east of the Lower Colorado River Valley. High temperatures over the central deserts will stay neaer seasonal normals, with hotter conditions over the western deserts. Storm chances on the lower deserts will be slight, with better chances over the higher terrain and over southeast Arizona. During the latter half of the week, storm chances will dwindle, and temperatures will increase to above normal levels. && .DISCUSSION... Monsoon circulation remains entrenched across Arizona with an impressive plume of deep moisture spreading north from northwest Mexico and running north/northeastward across central and eastern Arizona, around the periphery of a very strong upper high centered over the south-central CONUS. This moist plume is easily seen in the current IR and vapor imagery loops. Steering flow across central/eastern AZ is mostly south to southeast, becoming more southwesterly as you move west and into the far southwest AZ deserts and over SE California. Orientation of this flow will keep most of the convection focused over south-central Arizona this week with very little expected into the SE California deserts. PWAT value at Phoenix from the last 00z raob was healthy at 1.64 inches and there was modest CAPE present in the sounding. 2 am surface dewpoints over the central deserts were elevated, ranging mostly from the upper 50s to middle 60s. Little if any shower activity was noted early this morning on radar, just a fair amount of debris cloudiness spreading north across the lower deserts. Overall, for the next couple of days, we are looking at a low to medium grade monsoon in terms of thunderstorm coverage. Most of the convection will be located over south-central Arizona with slight chances of mainly afternoon and evening storms becoming 30 percent or more over the higher terrain east of Phoenix. Steering flow is not especially strong as the 700-300mb mean winds typically run 10- 15 knots, and most of the disturbances that will rotate around the high and serve as "triggers" for convection are not especially dynamical. Latest vapor imagery loop does show a moderately organized inverted trof spinning over NW Mexico, poised to move into southeast Arizona this morning and across portions of south central and east-central AZ during the day, but it is forecast to weaken as it moves through the area so most of the desert POPs will stay below 25 percent this evening. High temperatures over the central deserts today and Wednesday will stay near seasonal normals due to the elevated humidity, with highs reaching or exceeding 110 over the western deserts where the airmass is drier and there will be more solar insolation. Thursday through Saturday...monsoon moisture is forecast to thin a little as drier air from New Mexico and Colorado mix over the area. At the same time atmospheric height and thickness values increase dramatically over the region, and if it weren`t for remnant monsoon moisture, afternoon temperatures would be much higher. Therefore afternoon desert temperatures are forecast to be above the 110 degree mark, but approaching 115 over the driest low humidity area of southeast CA. We still expect high temperatures to generally stay just below excessive heat warning thresholds during the hottest days such as Friday and Saturday; this is supported by HIL data. By Friday, rain chances in the Phoenix area will struggle to exceed around 10 percent due to the drier air in place. Sunday into Monday...The strong upper high continues to build towards the west, with one high center eventually setting up over central CA. Flow around the high becomes more favorable from the east and monsoon moisture starts to return. As such thunderstorm chances start to rise and we will be seeing lower grade conditions with slight chances for afternoon convection over the lower central deserts, along with 20-30 percent chances across the higher terrain of southern Gila County. Temperatures will trend down slightly as humidity levels rise. && .AVIATION... South-Central Arizona Including KPHX, KIWA, and KSDL: Outside of a slight chance for a shower/weak thunderstorm later tonight as debris clouds from storms over northern Mexico move over the region, the rest of tonight and Tuesday morning should be quiet, with winds mainly out of a southeasterly direction. There is a slight risk of more convective activity on Tue afternoon, but confidence is too low to include it in the tafs at this time. Winds on Tue afternoon to once again become westerly, with speeds mainly in the 8-10 knot range. Southeast California/Southwest Arizona including KIPL and KBLH: Minimal aviation concerns through Tuesday morning with storm activity remaining well east over central AZ. Under mostly clear skies, sfc winds will favor a southerly direction at KIPL and from a southeasterly direction at KBLH. A few higher gusts will be possible at KBLH, but speeds should generally remain at or below 15kt. Aviation Discussion not updated for amended TAFs. && .FIRE WEATHER... Thursday through Monday... Temperatures will trend back into an above normal range through the weekend as better quality moisture partially scours out.Thunderstorm and wetting rain chances dwindle substantially and become almost exclusively limited to higher terrain north and east of Phoenix. Consequently, afternoon humidity levels near a 15- 30 percent range during the middle of the week will fall closer to a 10-25 percent range into the weekend. Outside of isolated gusty winds surrounding any thunderstorms, directions will favor an upslope component in the afternoon with gustiness around terrain features and light overnight valley drainage. && .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ Visit us on Facebook...Twitter...and at weather.gov/phoenix DISCUSSION...CB AVIATION...Percha/MO FIRE WEATHER...MO
Area Forecast Discussion National Weather Service Tucson AZ 250 AM MST TUE JUL 19 2016 .SYNOPSIS...Adequate moisture will provide scattered mainly afternoon and evening showers and thunderstorms through Wednesday. A slight decrease in daily coverage of showers and thunderstorms should then occur Thursday into this weekend. Expect near normal daytime temperatures Tuesday followed by a pronounced warming trend later this week. && .DISCUSSION...Isolated light showers were occurring early this morning east of Tucson. Expect these to continue thru sunrise as they move to the WNW. A weak MCV was over SW Graham county as of 2 am, but shouldn`t be a player today as it continue to move NNW. What could be a player later today is the inverted trof currently over Chihuahua MX. This feature is moving slowly to the NW toward the area. Hi-res models focusing best activity W of Tucson, with potential for blowing dust across Pinal county towards Phoenix, and Cochise county. PW values across the remain above normal for July so locally heavy rain a threat. Can`t rule out a severe storm or two. Highs today will be around normal. Scattered afternoon/evening storms Wednesday with highs slightly warmer than today. Starting Thursday and continuing through the upcoming weekend there will be a gradual decrease in shower and thunderstorm activity as sub-tropical ridge expands over the southern CONUS. Still hanging on to enough moisture to keep isolated to scattered storms in the forecast. Highs temperatures will be above normal through this period, maxing out on Friday. && .AVIATION...VALID THRU 20/12Z. Isolated showers through the early morning hours. Sct-bkn clouds at 6-9k ft agl and bkn-ovc clouds at 10-14k ft agl. Expect isolated to scattered showers and thunderstorms developing during the late morning and afternoon, persisting through the mid evening hours tonight. Brief wind gusts of 35-40 kts and MVFR conditions may occur with the stronger TSRA. Outside of thunderstorm outflows, sfc wind will generally be less than 12 kts through Wednesday morning. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Ample moisture will ensure daily chances of mainly afternoon and evening showers and thunderstorms this week. A slight decrease in rain chances will occur late in the week into the weekend along with an increase in daytime temperatures. Outside of gusty thunderstorm/outflow winds, expect typical diurnal 20-ft wind patterns each day at mainly less than 15 mph. && .CLIMATE...As the area heats up again, could see a few spots across the western deserts approach record highs later in the week. && .TWC WATCHES/WARNINGS/ADVISORIES...None. && $$ Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Area Forecast Discussion National Weather Service Flagstaff AZ 242 AM MST TUE JUL 19 2016 .SYNOPSIS...Monsoon moisture will continue to bring a chance of showers and thundertorms through Thursday. Strong high pressure and drier air could result in a downturn in activity toward the end of the week. && .DISCUSSION...A wide area of high pressure aloft remained centered over the Oklahoma/Kansas border. The models continue to promise little movement in this high pressure feature over the next few days. The position of the high is placing southerly flow over Arizona with not much change in the moisture profile through Thursday. Moving forward the distribution of showers and thunderstorms will remain very similar to Monday. Isolated heavy rain amounts of an inch or more and localized flooding will be possible. More generally, amounts in the trace to quarter inch category scattered about northern Arizona. From Friday onward...Models show the high pressure system centered over Oklahoma essentially splitting. The western portion of the high will migrate across Arizona and eventually become established over the western United States. If this pattern transpires it will open the door to an influx of drier air from the west. Forecast grids reflect a downturn in monsoon activity but moisture looks too entrenched for a complete shutdown in monsoon activity. We`ll keep you updated. && .AVIATION...For the 12Z package....Primarily VFR conditions are expected for the next 24 hours with bkn cigs aoa 14kft msl. til 17z isolated -shra / tsra possible, then btwn 17z-02z sct-nmrs SHRA/TSRA especially mountain areas. Brief visibility reductions and gusty winds possible near storms. Precipitation coverage decreasing after 02z Weds. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Expect another round of thunderstorms over the forecast area today and Wednesday. Storm motion will generally be from the south to north 5-10 mph. Thursday through Saturday...Scattered thunderstorms will persist across the area on Thursday. Drier air filtering into Arizona from the west will bring a decrease in thunderstorm activity on Friday and Saturday...with minimum RH`s dropping back into the teens to the north and west of Flagstaff. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC...McCollum AVIATION...DL For Northern Arizona weather information visit weather.gov/flagstaff
Area Forecast Discussion National Weather Service Tucson AZ 934 PM MST MON JUL 18 2016 .SYNOPSIS...Adequate moisture will provide scattered mainly afternoon and evening showers and thunderstorms through Wednesday. A slight decrease in daily coverage of showers and thunderstorms should then occur Thursday into this weekend. Expect near normal daytime temperatures Tuesday followed by a pronounced warming trend later this week. && .DISCUSSION...Showers and thunderstorms across southeast Arizona had diminished significantly in areal coverage late this evening. A few lingering showers and thunderstorms may continue to impact areas near Douglas through midnight, but not much activity expected thereafter. That said, updated the forecast to reflect this decreasing trend. Please refer to the additional sections in this product for more details. && .AVIATION...VALID THRU 20/06Z. A few lingering showers and thunderstorms can be expected tonight near the International Border. Otherwise, scattered to broken clouds at or above 10kft can be expected through Tuesday morning. Expect afternoon cloud build-ups Tuesday afternoon with isolated to scattered showers and thunderstorms developing through Tuesday evening. Brief wind gusts of 35-40 kts and MVFR conditions may occur with the stronger TSRA on Tuesday. Outside of thunderstorm outflows, sfc wind will generally be less than 12 kts through Tuesday afternoon. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Ample moisture will ensure daily chances of mainly afternoon and evening showers and thunderstorms this week. A slight decrease in rain chances will occur late in the week into the weekend along with an increase in daytime temperatures. Outside of gusty thunderstorm/outflow winds, expect typical diurnal 20-ft wind patterns each day at mainly less than 15 mph. && .PREV DISCUSSION...Similar coverage of showers/tstms as today canbe expected Tuesday afternoon/evening as deep (albeit still light)sely flow aloft continues across the area. Scattered mainly afternoon/evening showers/tstms will also occur Wednesday. Thereafter, the 18/12Z GFS/ECMWF/CMC were similar versus their respective solutions in depicting a gradual daily decrease in showers/tstms to begin Thursday and continue into this weekend. Given the continued ely mid-level flow, precip-free conditions area- wide should not occur as earlier this month. However, moisture should remain sufficient for isolated to scattered afternoon and evening showers and thunderstorms Thursday through next Monday. High temps Tuesday will remain quite close to seasonal normals. A warming trend is forecast to begin Wednesday, and based on various 18/12Z guidance, high temps were increased several degs Thur-Sat versus the previous forecast. At this time, appears that Friday will be the hottest day although Saturday should be quite similar. A moderation in daytime temps should then occur Sunday and Monday. && .TWC WATCHES/WARNINGS/ADVISORIES...None. && $$ Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Area Forecast Discussion National Weather Service Tucson AZ 934 PM MST MON JUL 18 2016 .SYNOPSIS...Adequate moisture will provide scattered mainly afternoon and evening showers and thunderstorms through Wednesday. A slight decrease in daily coverage of showers and thunderstorms should then occur Thursday into this weekend. Expect near normal daytime temperatures Tuesday followed by a pronounced warming trend later this week. && .DISCUSSION...Showers and thunderstorms across southeast Arizona had diminished significantly in areal coverage late this evening. A few lingering showers and thunderstorms may continue to impact areas near Douglas through midnight, but not much activity expected thereafter. That said, updated the forecast to reflect this decreasing trend. Please refer to the additional sections in this product for more details. && .AVIATION...VALID THRU 20/06Z. A few lingering showers and thunderstorms can be expected tonight near the International Border. Otherwise, scattered to broken clouds at or above 10kft can be expected through Tuesday morning. Expect afternoon cloud build-ups Tuesday afternoon with isolated to scattered showers and thunderstorms developing through Tuesday evening. Brief wind gusts of 35-40 kts and MVFR conditions may occur with the stronger TSRA on Tuesday. Outside of thunderstorm outflows, sfc wind will generally be less than 12 kts through Tuesday afternoon. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Ample moisture will ensure daily chances of mainly afternoon and evening showers and thunderstorms this week. A slight decrease in rain chances will occur late in the week into the weekend along with an increase in daytime temperatures. Outside of gusty thunderstorm/outflow winds, expect typical diurnal 20-ft wind patterns each day at mainly less than 15 mph. && .PREV DISCUSSION...Similar coverage of showers/tstms as today canbe expected Tuesday afternoon/evening as deep (albeit still light)sely flow aloft continues across the area. Scattered mainly afternoon/evening showers/tstms will also occur Wednesday. Thereafter, the 18/12Z GFS/ECMWF/CMC were similar versus their respective solutions in depicting a gradual daily decrease in showers/tstms to begin Thursday and continue into this weekend. Given the continued ely mid-level flow, precip-free conditions area- wide should not occur as earlier this month. However, moisture should remain sufficient for isolated to scattered afternoon and evening showers and thunderstorms Thursday through next Monday. High temps Tuesday will remain quite close to seasonal normals. A warming trend is forecast to begin Wednesday, and based on various 18/12Z guidance, high temps were increased several degs Thur-Sat versus the previous forecast. At this time, appears that Friday will be the hottest day although Saturday should be quite similar. A moderation in daytime temps should then occur Sunday and Monday. && .TWC WATCHES/WARNINGS/ADVISORIES...None. && $$ Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Area Forecast Discussion National Weather Service Flagstaff AZ 902 PM MST MON JUL 18 2016 .SYNOPSIS...Monsoon moisture will continue to bring a chance of showers and thundertorms through Thursday. Strong high pressure and drier air could result in a downturn in activity toward the end of the week. && .DISCUSSION... Thunderstorm activity appears to be trending downward this evening, with just a few isolated thunderstorms remaining. Will continue to monitor storms overnight, but the short-term forecast through morning currently looks in good shape. && .PREV DISCUSSION /250 PM MST/... The monsoon circulation has brought plentiful atmospheric moisture back into to the area...with precipitable water values now up to around 1.0" at KFLG. Instability has been somewhat limited...but scattered thunderstorms have formed with a few locally heavy showers, mainly over the higher terrain. Little change in the overall pattern is anticipated through Thursday with the strong ridge of high pressure in place over the Southern Plains and moist southerly flow over Arizona, providing the environment for daily thunderstorm activity across the forecast area. Storms will move a bit slower Tuesday through Thursday, leading to a somewhat greater chance for heavy rainfall accumulations. Friday through Sunday...forecast models continue to show the flattening of the ridge over the southern Rockies, and a decrease in thunderstorm activity Friday through Sunday as drier air filters in from the west. && .AVIATION...For the 00Z package...Only isolated showers and thunderstorms are expected for the remainder of tonight. Storms are likely to become more numerous again after 17Z Tuesday. Expect visibility reductions and gusty winds near stronger storms Tuesday. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Monsoon moisture is increasing across the area. Expect increasing showers and thunderstorm coverage. Gusty outflow winds are probable from any storms or showers, especially today. Storm motion today from south to north about 10 mph. Tuesday through Friday...Monsoon moisture to remain over northern Arizona, with shower and thunderstorm chances each day. Winds may become erratic and gusty near thunderstorms. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC...KD/Bohlin AVIATION...KD FIRE WEATHER...BAK For Northern Arizona weather information visit weather.gov/flagstaff
Area Forecast Discussion National Weather Service Phoenix AZ 835 PM MST MON JUL 18 2016 .SYNOPSIS... An increase in clouds and humidity can be expected during the next few days along with a slight chance of showers and thunderstorms, mainly east of the Lower Colorado River Valley. High temperatures will also be a bit cooler. Storm chances on the lower deserts will be slight, with better chances over the higher terrain and over southeast Arizona. During the latter half of the week, storm chances will dwindle, and temperatures will increase to above normal levels. && .DISCUSSION... A very activity late afternoon/evening for a few selected spots across south-central AZ. The combination of increased moisture levels through the column (KPSR balloon sounding PWAT 1.64 inches) and a weak disturbance that moved northward into southern AZ from northern Mexico triggered scattered showers and thunderstorms late this afternoon over Pima County. Outflow from these storms generated locally dense blowing dust over Pinal County, which contributed to a multi-vehicle accident that shut down I-10 at MP 214 late this afternoon. Outflows from these storms also triggered a few new storms over the greater Phoenix area early this evening. The strongest storm produced 63 mph winds and 0.34 inch of rain at Sky Harbor and localized damaging winds/flooding across central Phoenix. A second storm produced gusty winds and heavy winds over Queen Creek/San Tan Valley. At this hour, all remaining storms are either over Gila County or moved northward into Yavapai County. As far as the forecast for the rest of the night is concerned, although there is still a slight chance of an isolated shower or thunderstorm later tonight as debris cloudiness move northward from the remains of storms south of the international border, it should be quiet over the vast majority of our cwa. with inherited forecasts still looking good. && .PREVIOUS DISCUSSION... Tonight...Elevated amounts of monsoon moisture have now securely covered most of AZ. Athough thermodynamics are there for a few afternoon and evening showers and thunderstorms over our forecast area in south central AZ, this region seems to be in between upper level forcing mechanisms in currently working in northern and southern AZ. With the advent of a fairly strong and unseasonably cold Pacific trof moving into the Pacific northwest, a rather strong southwesterly Jetstream maximum has developed over portions of eastern Nevada and Utah. Accelerating winds aloft, from lighter winds in northern AZ into the Utah flow, has developed an area of upper level speed divergence and resulting convection. To our south near the Mexican border, the approaching massive inverted trof, clearly seen in water vapor imagery over the Mexican state of Chihuahua, is spreading leading edge upper level difluence. Our portions of south central AZ, including areas near Phoenix, are under a relatively stable upper level anti-cyclonic flow regime. Therefore a low grade monsoon forecast is expected for the remainder of this afternoon and evening, i.e. a slight chance of showers and thunderstorms. This forecast is excluding the possibility of copious amounts of convective debris clouds from southern AZ moving north toward Phoenix tonight, and causing the possibility of showers and thunderstorms similar to late Sunday night. So far model forecasts are minimizing this possibility. Tuesday...our office staff eyes are now transfixed on the massive inverted trof seen in water vapor imagery over north central Mexico. Models the past two days have resolved this feature very well at the 300/250 mb level, and latest model forecasts continue the trend of moving the feature bodily into southern AZ, although in a weakened form later Tuesday and Tuesday night. Current model forecast are minimizing the effect of this system in south central AZ, including nearby Phoenix and surrounding areas. From a fundamental stand point this is questionable. Strong differential heating and with weakness aloft normally results in an enhanced threat for storms that can last well into the evening hours. For now we will go with our instincts and raise precip probability a bit in south central AZ for late Tuesday and Tuesday night, with even a slight chance going into Wednesday morning. Wednesday...Monsoon moisture will be still be entrenched over the region. With mid/upper level disturbances should depart the area, resulting in another low grade monsoon forecast for Wednesday afternoon and evening. Thursday through Monday...monsoon moisture is forecast to thin a little as drier air from New Mexico and Colorado mix over the area. At the same time atmospheric height and thickness values increase dramatically over the region, and if it weren`t for remnant monsoon moisture, afternoon temperatures would be much higher. Therefore afternoon desert temperatures are forecast to be above the 110 degree mark, but approaching 115 over the driest low humidity area of southeast CA. && .AVIATION... South-Central Arizona Including KPHX, KIWA, and KSDL: Outside of a slight chance for a shower/weak thunderstorm later tonight as debris clouds from storms over northern Mexico move over the region, the rest of tonight and Tuesday morning should be quiet, with winds mainly out of a southeasterly direction. There is a slight risk of more convective activity on Tue afternoon, but confidence is too low to include it in the tafs at this time. Winds on Tue afternoon to once again become westerly, with speeds mainly in the 8-10 knot range. Southeast California/Southwest Arizona including KIPL and KBLH: Minimal aviation concerns through Tuesday morning with storm activity remaining well east over central AZ. Under mostly clear skies, sfc winds will favor a southerly direction at KIPL and from a southeasterly direction at KBLH. A few higher gusts will be possible at KBLH, but speeds should generally remain at or below 15kt. Aviation Discussion not updated for amended TAFs. && .FIRE WEATHER... Thursday through Monday... Temperatures will trend back into an above normal range through the weekend as better quality moisture partially scours out.Thunderstorm and wetting rain chances dwindle substantially and become almost exclusively limited to higher terrain north and east of Phoenix. Consequently, afternoon humidity levels near a 15- 30 percent range during the middle of the week will fall closer to a 10-25 percent range into the weekend. Outside of isolated gusty winds surrounding any thunderstorms, directions will favor an upslope component in the afternoon with gustiness around terrain features and light overnight valley drainage. && .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ Visit us on Facebook...Twitter...and at weather.gov/phoenix DISCUSSION...Percha/Vasquez AVIATION...Percha/MO FIRE WEATHER...MO
Area Forecast Discussion National Weather Service Tucson AZ 325 PM MST MON JUL 18 2016 .SYNOPSIS...Adequate moisture will provide scattered mainly afternoon and evening showers and thunderstorms through Wednesday. A slight decrease in daily coverage of showers and thunderstorms should then occur Thursday into this weekend. Expect near normal daytime temperatures Tuesday followed by a pronounced warming trend later this week. && .DISCUSSION...Scattered to numerous showers and thunderstorms were occurring generally from the Tohono O`odham Nation southeastward into far southeast Pima County, Santa Cruz County, and extreme southwest Cochise County at this time. This area is within a northwest-to-southeast oriented axis of greatest instability as per SPC hourly mesoscale analysis of MUCAPE. Other isolated showers and thunderstorms were also occurring from southcentral Pinal County eastward into western Graham County. Storm motions were mainly northwest around 5-10 kts. IR satellite imagery depicted rapidly cooling cloud tops during the past hour with the showers/tstms across central Pima County. Have favored the Univ of AZ WRF-NAM for precip chances tonight. Thus, expect scattered to perhaps numerous showers/tstms across much of the area this evening. The main concern given relatively slow storm motions and precip water values of 1.25"-1.50" will be locally heavy rainfall. Have maintained a slight chance of showers/tstms late tonight for much of this forecast area. Have noted that the WRF- NAM depicts precip-free conditions late tonight into mid-morning Tuesday. Will defer to the evening shift to adjust PoPs perhaps downward as necessary. Similar coverage of showers/tstms is expected Tuesday afternoon/evening as deep (albeit still light) sely flow aloft continues across the area. Scattered mainly afternoon/evening showers/tstms will also occur Wednesday. Thereafter, the 18/12Z GFS/ECMWF/CMC were similar versus their respective solutions in depicting a gradual daily decrease in showers/tstms to begin Thursday and continue into this weekend. Given the continued ely mid-level flow, precip-free conditions area- wide should not occur as earlier this month. However, moisture should remain sufficient for isolated to scattered afternoon and evening showers and thunderstorms Thursday through next Monday. High temps Tuesday will remain quite close to seasonal normals. A warming trend is forecast to begin Wednesday, and based on various 18/12Z guidance, high temps were increased several degs Thur-Sat versus the previous forecast. At this time, appears that Friday will be the hottest day although Saturday should be quite similar. A moderation in daytime temps should then occur Sunday and Monday. && .AVIATION...VALID THRU 20/00Z. Isolated to scattered SHRA/TSRA will occur through the period, with the best chances during the afternoon and evening hours. Brief wind gusts of 35-40 kts and MVFR conditions may occur with the stronger TSRA. Outside of thunderstorm outflows, sfc wind will generally be less than 12 kts through Tuesday afternoon. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Ample moisture will ensure daily chances of mainly afternoon and evening showers and thunderstorms this week. A slight decrease in rain chances will occur late in the week into the weekend along with an increase in daytime temperatures. Outside of gusty thunderstorm/outflow winds, expect typical diurnal 20-ft wind patterns each day at mainly less than 15 mph. && .TWC WATCHES/WARNINGS/ADVISORIES...None. && $$ DISCUSSION...Francis AVIATION/FIRE WEATHER...French Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Area Forecast Discussion National Weather Service Flagstaff AZ 250 PM MST MON JUL 18 2016 .SYNOPSIS...Monsoon moisture will continue to bring a chance of showers and thundertorms through Thursday. Strong high pressure and drier air could result in a downturn in activity toward the end of the week. && .DISCUSSION... The monsoon circulation has brought plentiful atmospheric moisture back into to the area...with precipitable water values now up to around 1.0" at KFLG. Instability has been somewhat limited...but scattered thunderstorms have formed with a few locally heavy showers, mainly over the higher terrain. Little change in the overall pattern is anticipated through Thursday with the strong ridge of high pressure in place over the Southern Plains and moist southerly flow over Arizona, providing the environment for daily thunderstorm activity across the forecast area. Storms will move a bit slower Tuesday through Thursday, leading to a somewhat greater chance for heavy rainfall accumulations. Friday through Sunday...forecast models continue to show the flattening of the ridge over the southern Rockies, and a decrease in thunderstorm activity Friday through Sunday as drier air filters in from the west. && .AVIATION...For the 00Z package...Sct shra/tsra expected to continue through 03z...with isold -shra/-tsra continuing overnight. Sct shra/tsra will redevelop after 18Z Tuesday...with storms most numerous over the higher terrain. Expect visibility reductions and gusty winds near storms. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Expect another round of thunderstorms over the forecast area Tuesday and Wednesday. Storm motion will generally be from the south to north 5-10 mph. Thursday through Saturday...Scattered thunderstorms will persist across the area on Thursday. Drier air filtering into Arizona from the west will bring a decrease in thunderstorm activity on Friday and Saturday...with minimum RH`s dropping back into the teens to the north and west of Flagstaff. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC...Bohlin/BAK AVIATION...BAK FIRE WEATHER...BAK For Northern Arizona weather information visit weather.gov/flagstaff
Area Forecast Discussion National Weather Service Phoenix AZ 200 PM MST MON JUL 18 2016 .SYNOPSIS... An increase in clouds and humidity can be expected during the next few days along with a slight chance of showers and thunderstorms, mainly east of the Lower Colorado River Valley. High temperatures will also be a bit cooler. Storm chances on the lower deserts will be slight, with better chances over the higher terrain and over southeast Arizona. During the latter half of the week, storm chances will dwindle, and temperatures will increase to above normal levels. && .DISCUSSION... Tonight...Elevated amounts of monsoon moisture have now securely covered most of AZ. Athough thermodynamics are there for a few afternoon and evening showers and thunderstorms over our forecast area in south central AZ, this region seems to be inbetween upper level forcing mechanisms in currently working in northern and southern AZ. With the advent of a fairly strong and unseasonably cold Pacific trof moving into the Pacific northwest, a rather strong southwesterly Jetstream maximum has developed over portions of eastern Nevada and Utah. Accelerating winds aloft, from lighter winds in northern AZ into the Utah flow, has developed an area of upper level speed divergence and resulting convection. To our south near the Mexican border, the approaching massive inverted trof, clearly seen in water vapor imagery over the Mexican state of Chihuahua, is spreading leading edge upper level difluence. Our portions of south central AZ, including areas near Phoenix, are under a relatively stable upper level anti-cyclonic flow regime. Therefore a low grade monsoon forecast is expected for the remainder of this afternoon and evening, i.e. a slight chance of showers and thunderstorms. This forecast is excluding the possibility of copious amounts of convective debris clouds from southern AZ moving north toward Phoenix tonight, and causing the possibility of showers and thunderstorms similar to late Sunday night. So far model forecasts are minimizing this possibility. Tuesday...our office staff eyes are now transfixed on the massive inverted trof seen in water vapor imagery over north central Mexico. Models the past two days have resolved this feature very well at the 300/250 mb level, and latest model forecasts continue the trend of moving the feature bodily into southern AZ, although in a weakened form later Tuesday and Tuesday night. Current model forecast are minimizing the effect of this system in south central AZ, including nearby Phoenix and surrounding areas. From a fundamental stand point this is questionable. Strong differential heating and with weakness aloft normally results in an enhanced threat for storms that can last well into the evening hours. For now we will go with our instincts and raise precip probability a bit in south central AZ for late Tuesday and Tuesday night, with even a slight chance going into Wednesday morning. Wednesday...Monsoon moisture will be still be entrenched over the region. With mid/upper level disturbances should depart the area, resulting in another low grade monsoon forecast for Wednesday afternoon and evening. Thursday through Monday...monsoon moisture is forecast to thin a little as drier air from New Mexico and Colorado mix over the area. At the same time atmospheric height and thickness values increase dramatically over the region, and if it weren`t for remnant monsoon moisture, afternoon temperatures would be much higher. Therefore afternoon desert temperatures are forecast to be above the 110 degree mark, but approaching 115 over the driest low humidity area of southeast CA. && .AVIATION... South-Central Arizona Including KPHX, KIWA, and KSDL: Timing wind shifts and the potential for gusty outflow winds and localized blowing dust will be the primary aviation concerns through Tuesday morning. Some variability about a southerly wind direction is likely again this afternoon, though eventually should favor southwest by the evening. Thunderstorms forming over SE AZ should move north towards the Phoenix area late in the afternoon with gusty outflow winds preceding them. While the threat of a storm directly affecting an airport is better than Sunday, probabilities are still quite low with better chances of localized blowing dust and more widespread lofted dust and haze affecting slantwise visibilities. Only modest confidence exists timing outflow wind shifts into terminal sites between 02Z- 04Z. Otherwise, developing cigs in a 10K-15K ft range look likely from decaying storms to the south. Southeast California/Southwest Arizona including KIPL and KBLH: Minimal aviation concerns through Tuesday morning with storm activity remaining well east into central AZ. Under mostly clear skies, sfc winds will favor a southerly direction, though will be more variable at KIPL after sunset. A few higher gusts will be possible, but speeds should generally remain at or below 15kt. Aviation Discussion not updated for amended TAFs. && .FIRE WEATHER... Thursday through Monday... Temperatures will trend back into an above normal range through the weekend as better quality moisture partially scours out.Thunderstorm and wetting rain chances dwindle substantially and become almost exclusively limited to higher terrain north and east of Phoenix. Consequently, afternoon humidity levels near a 15- 30 percent range during the middle of the week will fall closer to a 10-25 percent range into the weekend. Outside of isolated gusty winds surrounding any thunderstorms, directions will favor an upslope component in the afternoon with gustiness around terrain features and light overnight valley drainage. && .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ Visit us on Facebook...Twitter...and at weather.gov/phoenix DISCUSSION...Vasquez FIRE WEATHER...MO
Area Forecast Discussion National Weather Service Phoenix AZ 1230 PM MST MON JUL 18 2016 ...Updated Aviation and Fire Weather... .SYNOPSIS... An increase in clouds and humidity can be expected during the next few days along with a slight chance of showers and thunderstorms, mainly east of the Lower Colorado River Valley. High temperatures will also be a bit cooler. Storm chances on the lower deserts will be slight, with better chances over the higher terrain and over southeast Arizona. During the latter half of the week, storm chances will dwindle and temperatures will increase to above normal levels. && .DISCUSSION... Woohoo, the monsoon moisture boundary raced north past Phoenix over night and this morning was seen pushing up against the higher elevations of the Mogollon Rim. In other words the southern half of AZ was in the monsoon moisture soup, and noted by the relatively low afternoon convective trigger temperatures at a few locations. For example, based on this mornings weather balloon soundings, the convective trigger temp at Phoenix is 99 deg F, 97 at Tucson, and 92 deg at Globe/Miami (elevation 3-4 thsd ft msl). Even though the afternoon thermodynamics are there, the flow aloft has, and will remain anti-cyclonic and relatively stable today and tonight. In other words, the situation for today favors low topped afternoon convection, mostly in the mountains with possible outflows toward the deserts sparking an isolated desert storm, with convection dissipating quickly after dark, unless. Unless like last night, a surge of convective debris clouds from southeast AZ spread north, creating a well saturated mid level airmass that a gravity wave sparked a few showers and thunderstorms in the Phoenix area after midnight. The gravity wave conclusion was derived from high speed satellite imagery loops. Beyond today, our office staff eyes are now on the massive inverted trof seen in water vapor imagery over the north central Mexican state of Chihuahua. Models the past two days have resolved this feature very well at the 300/250 mb level, and is forecast to move into southeast AZ on Tuesday. For now the low grade monsoon forecast, meaning slight chance of showers and thunderstorms over the south central AZ deserts and mountains look ok for now. We will see how the new models handle Tuesdays inverted trof since model guidance will have incorporated the Chihuahua weather balloon sounding that is launched once per day at 12z. .Previous discussion...503 AM MST... The weather pattern has finally allowed the typical monsoonal circulation to return to the area as the combination of troffing along the Pacific northwest coast and upper ridging over the central CONUS has allowed southerly to southeasterly flow aloft to set up across Arizona. This favorable flow has advected considerable amounts of monsoon moisture into the lower deserts; the latest Phoenix raob had PWAT up to 1.44 inches and Tucson had 1.5 inches. Despite the ample moisture, much of it was at mid and upper levels through, limiting CAPE values. According to the 2 am SPC mesoanalysis graphic, MLCAPE of consequence (over 500 j/kg) was still over far SE Arizona with very low amounts in the central deserts. 2 am radar continued to show showers spreading into south central Arizona from the southeast and isolated thunderstorms are possible but any convection that develops should stay on the weak side into the morning hours. The convection is likely being aided by weak vort maxes rotating into Arizona around the large scale upper high. Should significant clouds and showers persist well into the morning or the early afternoon, instability will again be limited and storm activity tonight will suffer. For the next few days, operational models such as the GFS and ECMWF as well as GEFS data, call for the monsoonal circulation to remain in place with little change from day to day. Moisture will remain relatively plentiful, at least from a PWAT perspective as values upwards of 1.5 inches will stay over much of the lower deserts to the east of the lower Colorado river valley. Most of the CAPE of consequence however is advertised to stay pretty much from Maricopa county eastward each day, suggesting convective potential over the southwest deserts will be limited, and minimal as you move into the deserts of southeast California. Steering flow each day will stay south to southeast but not overly strong, with 700-300mb layer winds mostly between 10 and 15 knots each day. There will be occasional vort maxes/weak inverted trofs rotating around the main upper high and moving north across the central deserts but due to the small scale of these features, they will not be handled very well by the models and as such there will be low confidence in any particular one of these small scale features. As such we will keep a rather low grade monsoon forecast in place today through Wednesday with slight chances for mainly afternoon and evening showers and thunderstorms over the central lower deserts, with better chances over the higher terrain east of Phoenix. Skies will be partly to mostly cloudy much of the time, with the greatest amounts of sunshine likely during later morning through mid afternoon each day. High temperatures will stay near seasonal normals over south central Arizona today, then gradually creep up each day with Phoenix approaching 110 by Wednesday. It will be hotter over the far western deserts and over SE California as the airmass will be drier there. Thursday through Sunday...monsoon moisture is forecast to thin a little as drier air from New Mexico and Colorado mix over the area. At the same time atmospheric height and thickness values increase dramatically over the region, and if it weren`t for remnant monsoon moisture, afternoon temperatures be much higher. The driest areas Thursday through Sunday will be southeast California where afternoon temperatures at Imperial, El Centro, and Blythe will at the 114 degree mark. Ouch! Current forecasts will keep Phoenix at or above the 110 degree mark each day. At the moment it appears high temperature will stay below excessive heat warning thresholds but that could change depending upon just how dry we actually get, and how high the heights become over the lower deserts. && .AVIATION... South-Central Arizona Including KPHX, KIWA, and KSDL: Timing wind shifts and the potential for gusty outflow winds and localized blowing dust will be the primary aviation concerns through Tuesday morning. Some variability about a southerly wind direction is likely again this afternoon, though eventually should favor southwest by the evening. Thunderstorms forming over SE AZ should move north towards the Phoenix area late in the afternoon with gusty outflow winds preceding them. While the threat of a storm directly affecting an airport is better than Sunday, probabilities are still quite low with better chances of localized blowing dust and more widespread lofted dust and haze affecting slantwise visibilities. Only modest confidence exists timing outflow wind shifts into terminal sites between 02Z- 04Z. Otherwise, developing cigs in a 10K-15K ft range look likely from decaying storms to the south. Southeast California/Southwest Arizona including KIPL and KBLH: Minimal aviation concerns through Tuesday morning with storm activity remaining well east into central AZ. Under mostly clear skies, sfc winds will favor a southerly direction, though will be more variable at KIPL after sunset. A few higher gusts will be possible, but speeds should generally remain at or below 15kt. Aviation Discussion not updated for amended TAFs. && .FIRE WEATHER... Thursday through Monday... Temperatures will trend back into an above normal range through the weekend as better quality moisture partially scours out.Thunderstorm and wetting rain chances dwindle substantially and become almost exclusively limited to higher terrain north and east of Phoenix. Consequently, afternoon humidity levels near a 15- 30 percent range during the middle of the week will fall closer to a 10-25 percent range into the weekend. Outside of isolated gusty winds surrounding any thunderstorms, directions will favor an upslope component in the afternoon with gustiness around terrain features and light overnight valley drainage. && .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ Visit us on Facebook...Twitter...and at weather.gov/phoenix DISCUSSION...Vasquez/CB/Vasquez AVIATION...MO FIRE WEATHER...MO
Area Forecast Discussion National Weather Service Phoenix AZ 1230 PM MST MON JUL 18 2016 ...Updated Aviation and Fire Weather... .SYNOPSIS... An increase in clouds and humidity can be expected during the next few days along with a slight chance of showers and thunderstorms, mainly east of the Lower Colorado River Valley. High temperatures will also be a bit cooler. Storm chances on the lower deserts will be slight, with better chances over the higher terrain and over southeast Arizona. During the latter half of the week, storm chances will dwindle and temperatures will increase to above normal levels. && .DISCUSSION... Woohoo, the monsoon moisture boundary raced north past Phoenix over night and this morning was seen pushing up against the higher elevations of the Mogollon Rim. In other words the southern half of AZ was in the monsoon moisture soup, and noted by the relatively low afternoon convective trigger temperatures at a few locations. For example, based on this mornings weather balloon soundings, the convective trigger temp at Phoenix is 99 deg F, 97 at Tucson, and 92 deg at Globe/Miami (elevation 3-4 thsd ft msl). Even though the afternoon thermodynamics are there, the flow aloft has, and will remain anti-cyclonic and relatively stable today and tonight. In other words, the situation for today favors low topped afternoon convection, mostly in the mountains with possible outflows toward the deserts sparking an isolated desert storm, with convection dissipating quickly after dark, unless. Unless like last night, a surge of convective debris clouds from southeast AZ spread north, creating a well saturated mid level airmass that a gravity wave sparked a few showers and thunderstorms in the Phoenix area after midnight. The gravity wave conclusion was derived from high speed satellite imagery loops. Beyond today, our office staff eyes are now on the massive inverted trof seen in water vapor imagery over the north central Mexican state of Chihuahua. Models the past two days have resolved this feature very well at the 300/250 mb level, and is forecast to move into southeast AZ on Tuesday. For now the low grade monsoon forecast, meaning slight chance of showers and thunderstorms over the south central AZ deserts and mountains look ok for now. We will see how the new models handle Tuesdays inverted trof since model guidance will have incorporated the Chihuahua weather balloon sounding that is launched once per day at 12z. .Previous discussion...503 AM MST... The weather pattern has finally allowed the typical monsoonal circulation to return to the area as the combination of troffing along the Pacific northwest coast and upper ridging over the central CONUS has allowed southerly to southeasterly flow aloft to set up across Arizona. This favorable flow has advected considerable amounts of monsoon moisture into the lower deserts; the latest Phoenix raob had PWAT up to 1.44 inches and Tucson had 1.5 inches. Despite the ample moisture, much of it was at mid and upper levels through, limiting CAPE values. According to the 2 am SPC mesoanalysis graphic, MLCAPE of consequence (over 500 j/kg) was still over far SE Arizona with very low amounts in the central deserts. 2 am radar continued to show showers spreading into south central Arizona from the southeast and isolated thunderstorms are possible but any convection that develops should stay on the weak side into the morning hours. The convection is likely being aided by weak vort maxes rotating into Arizona around the large scale upper high. Should significant clouds and showers persist well into the morning or the early afternoon, instability will again be limited and storm activity tonight will suffer. For the next few days, operational models such as the GFS and ECMWF as well as GEFS data, call for the monsoonal circulation to remain in place with little change from day to day. Moisture will remain relatively plentiful, at least from a PWAT perspective as values upwards of 1.5 inches will stay over much of the lower deserts to the east of the lower Colorado river valley. Most of the CAPE of consequence however is advertised to stay pretty much from Maricopa county eastward each day, suggesting convective potential over the southwest deserts will be limited, and minimal as you move into the deserts of southeast California. Steering flow each day will stay south to southeast but not overly strong, with 700-300mb layer winds mostly between 10 and 15 knots each day. There will be occasional vort maxes/weak inverted trofs rotating around the main upper high and moving north across the central deserts but due to the small scale of these features, they will not be handled very well by the models and as such there will be low confidence in any particular one of these small scale features. As such we will keep a rather low grade monsoon forecast in place today through Wednesday with slight chances for mainly afternoon and evening showers and thunderstorms over the central lower deserts, with better chances over the higher terrain east of Phoenix. Skies will be partly to mostly cloudy much of the time, with the greatest amounts of sunshine likely during later morning through mid afternoon each day. High temperatures will stay near seasonal normals over south central Arizona today, then gradually creep up each day with Phoenix approaching 110 by Wednesday. It will be hotter over the far western deserts and over SE California as the airmass will be drier there. Thursday through Sunday...monsoon moisture is forecast to thin a little as drier air from New Mexico and Colorado mix over the area. At the same time atmospheric height and thickness values increase dramatically over the region, and if it weren`t for remnant monsoon moisture, afternoon temperatures be much higher. The driest areas Thursday through Sunday will be southeast California where afternoon temperatures at Imperial, El Centro, and Blythe will at the 114 degree mark. Ouch! Current forecasts will keep Phoenix at or above the 110 degree mark each day. At the moment it appears high temperature will stay below excessive heat warning thresholds but that could change depending upon just how dry we actually get, and how high the heights become over the lower deserts. && .AVIATION... South-Central Arizona Including KPHX, KIWA, and KSDL: Timing wind shifts and the potential for gusty outflow winds and localized blowing dust will be the primary aviation concerns through Tuesday morning. Some variability about a southerly wind direction is likely again this afternoon, though eventually should favor southwest by the evening. Thunderstorms forming over SE AZ should move north towards the Phoenix area late in the afternoon with gusty outflow winds preceding them. While the threat of a storm directly affecting an airport is better than Sunday, probabilities are still quite low with better chances of localized blowing dust and more widespread lofted dust and haze affecting slantwise visibilities. Only modest confidence exists timing outflow wind shifts into terminal sites between 02Z- 04Z. Otherwise, developing cigs in a 10K-15K ft range look likely from decaying storms to the south. Southeast California/Southwest Arizona including KIPL and KBLH: Minimal aviation concerns through Tuesday morning with storm activity remaining well east into central AZ. Under mostly clear skies, sfc winds will favor a southerly direction, though will be more variable at KIPL after sunset. A few higher gusts will be possible, but speeds should generally remain at or below 15kt. Aviation Discussion not updated for amended TAFs. && .FIRE WEATHER... Thursday through Monday... Temperatures will trend back into an above normal range through the weekend as better quality moisture partially scours out.Thunderstorm and wetting rain chances dwindle substantially and become almost exclusively limited to higher terrain north and east of Phoenix. Consequently, afternoon humidity levels near a 15- 30 percent range during the middle of the week will fall closer to a 10-25 percent range into the weekend. Outside of isolated gusty winds surrounding any thunderstorms, directions will favor an upslope component in the afternoon with gustiness around terrain features and light overnight valley drainage. && .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ Visit us on Facebook...Twitter...and at weather.gov/phoenix DISCUSSION...Vasquez/CB/Vasquez AVIATION...MO FIRE WEATHER...MO
Area Forecast Discussion National Weather Service Flagstaff AZ 1004 AM MST MON JUL 18 2016 .SYNOPSIS...Monsoon moisture will continue to bring a chance of showers and thundertorms through Thursday. Strong high pressure and drier air could result in a downturn in activity toward the end of the week. && .DISCUSSION...The subtropical ridge remains in a favorable position for moisture advection into Arizona through Friday. This translates into a moderate grade Monsoon with good chances for showers and thunderstorms each day. A few storms will develop in the overnight periods as a few upper level 200-300mb disturbances roll across the state. We sent out a quick update to increase shower chances this evening. Otherwise the forecast grids look good. && .PREV DISCUSSION /430 AM MST/... For today through Thursday...Due to the position of the high southerly flow and monsoon moisture will remain over northern Arizona. There should be some increase in moisture values over Sunday so shower and thunderstorm activity is expected to be more widespread. Instability and strength of any storms will be inhibited by general mid to high level cloud cover and the fact that the pattern doesn`t favor a decent push of low level moisture. In other words, precipitation amounts will mostly remain on the low to modest side. From Friday onward...Models show strong high pressure aloft building across Arizona into California. As a result, a drier air mass will filter in from the west. Low to no grade monsoon activity will be the result should this pattern materialize. && .AVIATION...For the 18Z package...sct-nmrs shra/tsra expected to develop this afternoon...continuing through 03z. Brief visibility reductions and gusty winds possible near storms. isold-sct -shra will continue aft 05Z. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Monsoon moisture is increasing across the area. Expect increasing showers and thunderstorm coverage. Gusty outflow winds are probable from any storms or showers, especially today. Storm motion today from south to north about 10 mph. Tuesday through Friday...Monsoon moisture to remain over northern Arizona, with shower and thunderstorm chances each day. Winds may become erratic and gusty near thunderstorms. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC...Bohlin/McCollum AVIATION...BAK FIRE WEATHER...DL For Northern Arizona weather information visit weather.gov/flagstaff
Area Forecast Discussion National Weather Service Tucson AZ 915 AM MST MON JUL 18 2016 .SYNOPSIS...Adequate moisture will provide scattered mainly afternoon and evening showers and thunderstorms through Wednesday. A slight decrease in daily coverage of showers and thunderstorms should then occur Thursday into the upcoming weekend. && .DISCUSSION...Isolated showers were occurring in western Pima County east of Ajo at this time. Otherwise, visible satellite imagery depicted mostly clear skies to partly cloudy skies from Tucson westward into western Pima County, and mostly clear skies across eastern sections. Ample moisture exists with dewpoints at lower elevations valid 16Z ranging from the mid 50s-lower 60s. 18/12Z KTWC sounding total precip water value of 1.50" was about 0.15" higher versus 24 hours ago. 18/12Z upper air plots depicted a broad ridge over the southern CONUS, with a 597 DM high centered over northern Mississippi. Meanwhile, a deep upper trough was over the Pacific NW, and deep easterly/southeasterly flow prevailed across southeast AZ. Given the greater extent of clearing skies especially across eastern sections versus Sunday morning, am inclined to expect that shower/ tstm development later this morning will occur across favored ranges such as the Chiricahua Mountains. The 18/14Z HRRR supports this notion, the showers/tstms should migrate wwd/nwwd this afternoon. Quick glance at the 18/12Z Univ. of AZ WRF-NAM suggests shower/tstm development may also occur further westward by 19Z, and favor locales from Nogales to Kitt Peak. Water vapor imagery depicts a cyclonic twist approaching this area from the southeast over central Sonora Mexico. A much larger cyclonic circulation was south of the Texas Big Bend, or far eastern Chihuahua Mexico. This system may have more influence for this forecast area Tuesday. At any rate and without a further recitation of various NWP models, expect scattered to perhaps numerous showers and thunderstorms this afternoon and evening. The lowest coverage should occur across western Pima County where only isolated showers/tstms are expected. The main concern this afternoon/evening will be the potential for locally heavy rainfall and brief strong wind gusts that may approach severe thresholds. A slight chance of showers/tstms continues for much of the area late tonight. High temps this afternoon will be quite similar to temps achieved Sunday, or perhaps generally a couple of degs lower depending upon location. May make some minor PoP adjustments for this afternoon/evening, but this will not affect the overall scenario. Please refer to the additional sections for further detail. && .AVIATION...VALID THRU 19/18Z. Isolated -SHRA mainly west of KTUS this morning, then scattered to numerous -TSRA/-SHRA this afternoon and evening. The favored locales will be from KTUS vicinity east and south to the New Mexico/ International borders. Forecast confidence is sufficiently high to include VCTS in the KDUG/KOLS TAFs this afternoon and evening. VCTS may be delayed at KTUS until after 20/00Z. Isolated -SHRA and possible -TSRA to continue late tonight/early Tuesday morning. Outside of thunderstorm outflows, surface wind will generally be variable in direction less than 12 kts thru the period. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Ample moisture and a favorable flow regime will maintain the daily cycle of scattered to perhaps numerous showers and thunderstorms through Wednesday. The bulk of this activity will occur during the afternoon and evening hours, and a slight chance of showers and thunderstorms will continue during the overnight hours. Thereafter, a gradual decrease in thunderstorm coverage is expected Thursday into the upcoming weekend. Outside of gusty thunderstorm outflows, 20-foot winds will be terrain driven and mostly less than 15 mph. && .PREV DISCUSSION /340 AM MST/...The 330 am radar imagery showed a distinctive circulation just west of Willcox, moving to the WNW. This MCV is associated with decaying MCS that formed over eastern Cochise county last night and produced areas of locally heavy rain. Douglas airport recorded 1.75" last night which set a daily record and also ranks as the 9th wettest July day on record. The MCV will be one of several features that will have an impact on todays forecast. Last nights MCS likely associated with a weak disturbance aloft that moved across northern Chihuahua MX. Water vapor was also showing an inverted trof approaching the Texas Big Bend this morning. A challenging forecast indeed for the next 12-18 hours. One would go with the idea that after the morning activity ends, that there will be lesser activity this afternoon due to debris cloud cover slowly diminishing which cuts down on heating thus being a few degrees cooler than Sunday. However both HRRR and 00z WRF NAM/GFS fire scattered storms this afternoon. Confidence is low will this forecast. Tomorrow likely will be another forecast challenge based on what will transpire today. Again confidence is low. Wednesday through next weekend will see a gradual decrease in moisture and thus areal coverage of storms as the sub-tropical high expands west into the eastern Pacific. Temperature warming up but likely not as hot as the GFS would suggest if going by low-level thickness numbers, which are higher than EC. Something to keep watch. && .TWC WATCHES/WARNINGS/ADVISORIES...None. && $$ Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
557 PM CDT TUE JUL 19 2016 ...AVIATION UPDATE... .SHORT TERM...(This Evening through Wednesday) Issued at 315 PM CDT TUE JUL 19 2016 Tonight through Wednesday... An Excessive Heat Warning continues through Saturday. High temperatures this afternoon are ranging from the middle to upper 90s. These hot temperatures coupled with dewpoints in the low to middle 70s are producing heat indices near 105 degrees. A complex of showers and thunderstorms are located across Southern Iowa and Northern Missouri. These will remain well east of forecast area. Otherwise upper level ridging continues across the area into Wednesday. Overnight lows will only "cool" into the middle 70s. Any thunderstorm chances will stay north of KS-NE border overnight as weak 500MB waves ride up and over the ridge, along a stall surface boundary. Temperatures will once again warm into the middle 90s to perhaps 100 degrees Wednesday afternoon. With mid 70 dewpoints remaining in place across much of the area, heat indices will soar to between 105 and 110 degrees during the afternoon and evening. .LONG TERM...(Wednesday Night through Tuesday) Issued at 315 PM CDT TUE JUL 19 2016 The mid range forecast for Thursday and Friday will continue to be hot and dry with a broad upper high in place centered over the Southern Plains. This will continue to advect southwest flow into the Central Plains pushing H85 temps to the 27C range. The heat will likely continue into Saturday, which will be yet another day with heat index values reaching into the 105F range. Therefore, have extended the excessive heat warning into Saturday. Into the rest of the weekend, precip chances do increase as an upper level low advects through the Northern Plains into the Upper MS Valley. Main belt of Westerlies remains near the CONUS/Canadian border, but expect the broad ridge will begin to break down with minor shortwaves pulling out of the Rockies into the Central Plains providing at least weak DPVA to into portions of the outlook area. With best forcing just to the north of the Kansas/Nebraska border, but with a weak cold front entering the area and transitioning into a stationary boundary, expect that slight chances for showers and perhaps a few isolated thunderstorms kick off over portions of the area Sunday through Tuesday time frame. Not expecting severe storms at this time since shear profiles seem weak and disorganized with conditional mid level lapse rates. The added benefit of any precip at this point in the extended will likely be at least some cooling of temperatures which will bring heat index values into the mid to upper 90s which will seem a bit better than mid 100s. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening) Issued at 557 PM CDT TUE JUL 19 2016 Upper ridging should allow VFR conditions to prevail. There is some marginal risk for LLWS during the pre dawn hours. Forecast soundings are not very strong with the inversion so there is some indication the boundary layer may remained just mixed enough. Therefore will monitor conditions without adding LLWS to the forecast for now. && .TOP Watches/Warnings/Advisories... Excessive Heat Warning until 7 PM CDT Saturday for KSZ008>012- 020>024-026-034>040-054>056-058-059. && $$ SHORT TERM...Baerg LONG TERM...Drake AVIATION...Wolters
  [top] Area Forecast Discussion National Weather Service Goodland KS 415 PM MDT TUE JUL 19 2016 .SHORT TERM...(This afternoon through Wednesday) Issued at 147 PM MDT Tue Jul 19 2016 Early afternoon WV imagery and RAP upper level analysis show large scale ridge centered over the plains dominating the pattern across the US. Moist monsoonal plume is wrapping around the western extent of ridge into the Rockies. At the surface; low pressure is in place across eastern Colorado with a trough axis extending from northeast Colorado and across northern Kansas. Southwest flow is in place across much of our cwa. This afternoon-Wednesday: Mean storm track remains well west of our CWA with focus mainly in the central Rockies. A few weak shortwaves may try rotating towards the northwest part of our CWA. West and northwest parts of our CWA (near surface trough) also have better chance to see any thunderstorm activity due to weaker CAP and better instability. Further south and east in our CWA guidance shows a stronger CAP and eventually a significant decrease in CAPE as profiles warm and dry out during the afternoon periods. Strongest precip signal in guidance matches with these trends (northwest). A slightly stronger shortwave and shift in trough axis Wednesday (as indicated by some models) may support a few thunderstorms moving a little further east-southeast Wednesday afternoon (far northwest Kansas). Regarding temperatures/heat indices: Air mass aloft is only expected to become warmer and consensus shows highs 2-4F warmer than today. A major question on heat indices is Tds (which may mix lower in our west). As Tds decrease below 60 heat indices actually decrease from ambient temperature. Td recovery during the nighttime periods we will see overnight heat indices in the 68-76 range (minimum) which is quite mild for our CWA. There may be a few counties along western periphery of current heat advisory that remain below "exact" advisory criteria, but it is close enough and considering the very warm nighttime heat indices and several days in a row of the hot temperatures the decision was made to upgrade watch to heat advisory. Consecutive day requirement is not expected to be met for issuance of heat warning at this time, so advisory was favored. .LONG TERM...(Wednesday night through Tuesday) Issued at 213 PM MDT Tue Jul 19 2016 Overall, not much has changed in the long term. Hot temperatures are still the main story in the midterm while precipitation chances persist throughout the extended. Wednesday night through Friday, high pressure dominates the pattern. Above normal temperatures are anticipated with highs from the upper 90s to the low 100s on both Thursday and Friday, with Thursday being the hotter day for most locations. With dewpoint temperatures in the lower 60s, heat indices will be around 105 generally east of a line from Russell Springs, Kansas to Benkelman, Nebraska. This has warranted a heat headline for these locations. As mentioned in the short term discussion, the watch has been upgraded to a heat advisory (beginning Wednesday afternoon) and extended to cover through Friday afternoon. Expect somewhat dry conditions for the majority of the area, with only slight chances for convection each afternoon/evening as monsoonal moisture filters into the region along the western side of the ridge and disturbances pass through the upper flow. Friday night and the weekend, the ridge across the CONUS breaks down as a trough tracks from the Pacific Northwest and across the northern Plains, sending a cold front south. Will see more seasonal temperatures over the weekend. With a boundary nearby, expect thunderstorm chances through the weekend. Early next week, guidance differs on how the pattern develops. Consensus seems to be that the high pressure retreats to the west, bringing more of a west/northwest flow to the region. Some perturbations round the northern side of the high, traveling from the Rockies to the High Plains. This setup generates an opportunity for additional precipitation as the trough impacting the region during the weekend continues to push towards New England. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 415 PM MDT Tue Jul 19 2016 For KGLD and KMCK, vfr conditions expected through the period. Only a few mid and high clouds expected through the period. Winds begin the period from the south gusting around 25kts through 03z or so before falling to around 12kts with a few higher gusts. This continues overnight with a slight veering to the southwest around 10kts or so after 14z. Both terminals will see wind shear in the 05z-12z timeframe. && .GLD Watches/Warnings/Advisories... KS...Heat Advisory from noon Wednesday to 7 PM CDT Friday for KSZ002>004-014>016-028-029. CO...NONE. NE...Heat Advisory from 11 AM MDT /noon CDT/ Wednesday to 6 PM MDT /7 PM CDT/ Friday for NEZ079>081. && $$ SHORT TERM...DR LONG TERM...JBH AVIATION...99
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
333 PM CDT MON JUL 18 2016 .SHORT TERM...(This Evening through Tuesday) Issued at 329 PM CDT MON JUL 18 2016 At 20Z, water vapor imagery shows a cloud band with moisture streaming into the Central Rockies with another cloud band stretched from the northern Central Plains into the Ohio Valley up through the New England States. Some storms still along the stationary boundary at the surface into northwestern MO and extreme southeastern IA. Storms also beginning to fire over the foothills of the Rockies into the panhandle of Nebraska. In northeastern Kansas, forecasting a mostly dry period in the short term as heights continue to rise steadily overnight into the day on Tuesday. An MCS may develop overnight associated with the storms previously mentioned over the Rockies. These should stay to the north of the outlook area tonight though as the LLJ convergence is focused to our northwest. Only the NAM brings some of this activity close to the area with all the other short term guidance taking the storms on a northerly track into northern Nebraska and northwestern Iowa overnight. Therefore, not expecting much if any influence from a cold outflow to impact our area even though there is a brief period of isentropic lift that advects over the the region on the 315K to 320K surface. Lack of mid level moisture should keep storms to the north. That said, do expect temperatures to increase again tomorrow into the mid to upper 90s with dewpoints into the upper 60s and low 70s. This should continue to put heat index values into the 105F range while lowest heat index values will be at or above 75F. Have kept heat advisory going for the evening and have upgraded to a heat warning starting Tuesday afternoon as many days of at least heat advisory heat index values are expected. The bottom line is the heat will be the main forecast concern through the period. .LONG TERM...(Tuesday Night through Monday) Issued at 329 PM CDT MON JUL 18 2016 Tuesday night through Thursday... With upper high centered over the Southern/Central Plains during this period, and no real low-level convergence features expected to impact eastern KS, expect dry weather to continue. With dewpoints from the upper 60s to mid 70s, and afternoon high temperatures in the 96 to 103 degree range, afternoon heat indices should be in the 103 to 108 degree range. Overnight lows are only expected to fall to the mid to upper 70s. Thursday Night through Monday... A stout upper-level ridge will continue to be center of the central United States through the end of the week. High temperatures will soar into the upper 90s and lower 100s Friday afternoon. These very hot temperatures coupled with high dewpoints, heat indices will range from 105 to 110 degrees (possibly warmer). Saturday becomes a bit tricky as both the EC and GFS bring a weak cold front through portions of the area. Not only would it "cool" temperatures back into the lower to middle 90s, but precip chances also increase. The front appears to stall out in the vicinity of the outlook area for the remainder of the weekend. Guidance suggests weak 500MB waves will traverse the CWA along the surface boundary. Therefore, have at least slight chance PoPs across the area, along with cooler temperatures. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday Afternoon) Issued at 1227 PM CDT MON JUL 18 2016 For the 18Z TAFs, expect VFR conditions to prevail throughout the period. Winds should slowly veer to a more SSE component into the afternoon and evening. Slightly stronger winds near KMHK until around the 01Z time frame. && .TOP Watches/Warnings/Advisories... Excessive Heat Warning from 1 PM Tuesday to 7 PM CDT Friday for KSZ008>012-020>024-026-034>040-054>056-058-059. Heat Advisory until 1 PM CDT Tuesday for KSZ008>012-020>024-026- 034>040-054>056-058-059. && $$ SHORT TERM...Drake LONG TERM...Baerg/GDP AVIATION...Drake
Area Forecast Discussion National Weather Service Wichita KS 311 PM CDT MON JUL 18 2016 .SYNOPSIS... Issued at 311 PM CDT Mon Jul 18 2016 In the upper levels, water vapor imagery shows one shortwave tracking across western Quebec with another impulse rotating over the Pacific NW. Meanwhile, ridging is in place over the Rockies into the Plains. At the surface, weak lee troughing is in place with a weak front extending across northern MO into southern Nebraska. && .SHORT TERM...(This evening through Friday) Issued at 311 PM CDT Mon Jul 18 2016 The main theme for the next few days will be for the upper ridge to continue to build and expand over the Plains through Fri. This will allow for plenty of sun and a warming trend. Temps Tue look like the "coolest" through at least Fri before the more serious heat starts Wed and continues through the end of the work week. Should start to see more widespread highs at or above 100 by Wed. The only good news is that we should start to see afternoon dew points mix out for mid-late week which should limit the 110+ heat indices. Due to the prolonged period of 100-105+ heat, will continue with heat headlines along and east of I-135. .LONG TERM...(Saturday through Monday) Issued at 311 PM CDT Mon Jul 18 2016 Upper pattern will slowly start to flatten out starting Sat and continue into the start of the work week. There is also some model agreement in some shortwave energy sliding across the northern Plains and into the western Great Lakes region by Sun which may try and push a front into northern Kansas. In addition, the more zonal flow will allow some of the weak impulses to track over the area which may spark off a few storms. Confidence in storm chances through these periods is extremely low as models will have a hard time resolving these smaller scale features this far out. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) Issued at 1231 PM CDT Mon Jul 18 2016 Weak low pressure was centered near Hays at 1730Z. This was along a quasi-stationary boundary that extended from KGKC-KHYS. Mainly a wind forecast over the next 24 hours as a dome of upper level high pressure suppresses storm development across the area. Winds will primarily be from the south to southwest at 10-20 knots through the period. Cigs and vsbys VFR. && .PRELIMINARY POINT TEMPS/POPS... Wichita-KICT 73 96 75 100 / 0 0 0 0 Hutchinson 74 97 75 100 / 0 0 0 0 Newton 74 95 75 99 / 0 0 0 0 ElDorado 74 95 75 98 / 0 0 0 0 Winfield-KWLD 74 95 75 99 / 0 0 0 0 Russell 73 98 75 102 / 10 0 0 0 Great Bend 73 98 74 101 / 0 0 0 0 Salina 75 97 76 102 / 10 10 0 0 McPherson 73 97 75 100 / 0 0 0 0 Coffeyville 74 95 75 96 / 0 0 0 0 Chanute 74 94 74 95 / 0 0 0 0 Iola 73 94 74 95 / 10 0 0 0 Parsons-KPPF 73 94 74 95 / 0 0 0 0 && .ICT Watches/Warnings/Advisories... Heat Advisory until 8 PM CDT Friday for KSZ068>070-083-092>096- 098>100. Excessive Heat Warning from noon Tuesday to 8 PM CDT Friday for KSZ049-051>053-070>072. Heat Advisory until noon CDT Tuesday for KSZ049-051>053-071-072. && $$ SHORT TERM...RBL LONG TERM...RBL AVIATION...KRC
Area Forecast Discussion National Weather Service Goodland KS 205 PM MDT MON JUL 18 2016 .SHORT TERM...(This afternoon through Tuesday) Issued at 147 PM MDT Mon Jul 18 2016 Early afternoon satellite and RAP upper level analysis shows large scale ridge entrenched across the central US, with monsoonal flow in across through the central Rockies. A shortwave trough is currently rotating into northern Colorado/southern Wyoming with thunderstorms activity initiating in the higher terrain. A warm front is slowly progressing northward over our CWA and is still roughly south of I-70. Early this afternoon-Tonight: Warm front has been slower to lift north than models had previously indicated, however a strong CAP in place is limiting initiation within frontal zone. Thunderstorm activity may still initiate as the front lifts north and thunderstorms in Colorado may also begin to sneak into our far west before main area of thunderstorms develops this evening. As the shortwave moves out of the Rockies into western Nebraska this should help speed up the movement on the warm front and by 00z this feature should be near the northern part of our CWA. Higher resolution models support thunderstorms merging into a cluster or complex as LLJ increases this evening and then tracking over our far northwest and this is where I placed highest PoPs. There is a deep/moist air mass in place with PWATs exceeding 1.0" and Tds (within frontal zone) in the 60-70 range. Thunderstorm motions are expected to be around 15 kt and east-southeast flow overrunning the frontal zone could lead to training of thunderstorm activity. This raises the possibility for locally heavy rainfall amounts and at least a localized risk for flooding in our northwest. Initially CAPE will be favorable for severe thunderstorms, however deep layer sheer is very marginal and main CAPE axis will trend northward with front. Tuesday: Ridge continues to amplify shifting main flow further west away from our CWA. Some guidance is still hinting at isolated thunderstorms moving into northwest portions of Yuma county, however confidence is not high this will make it this far east. Slight chance PoPs were maintained for now. Temperatures will trend upwards with strengthening of the ridge and increasing southerly flow with high temperatures at least in the upper 90s for most locations and near 100 (to the low 100s) in our north and east. Heat index values appear to remain near 100F due to slightly lower Td values, so will hold off on any highlights. .LONG TERM...(Tuesday night through Monday) Issued at 205 PM MDT Mon Jul 18 2016 Hot temperatures are anticipated during the longterm period, with high pressure impacting the region into the weekend. Midweek appears to be mainly dry while precipitation chances persist throughout the extended. Tuesday night through Thursday night: High pressure remains centered over the CONUS and ridging dominates the pattern through midweek. Could see isolated thunderstorms in the northwestern portion of the area each afternoon/evening Tuesday and Wednesday as monsoonal moisture wraps around the western side of the ridge. The high pressure elongates over the southern half of the country on Thursday. Thunderstorm chances return to the region in the evening as the ridge begins to flatten. Friday through Monday: At the end of the work week, a shortwave pushes from the Pacific Northwest towards the northern Plains. This disturbance sends a cold front south Friday night into Saturday, bringing increased thunderstorm chances on Saturday and slightly cooler temperatures for the weekend/early next week. The ridge retreats to the west on Sunday and Monday, and a more active pattern develops over the High Plains with continued precipitation chances as disturbances move through the flow. Heat: Hot temperatures are expected on Wednesday and Thursday before a cooling trend in the extended. Highs top out in the upper 90s along and west of the Colorado border while temperatures in the 100-104 range are forecast to the east. With heat index values near 105 along and east of Highway 25, am thinking a heat advisory may be needed for at least Wednesday and Thursday. Temperatures look to trend downward from Friday onward with highs in the upper 80s to low 90s by Sunday. Lows will be in the 60s to mid 70s in the long term period. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) Issued at 1128 AM MDT Mon Jul 18 2016 Stratus/fog has cleared at both terminals and VFR conditions should prevail at KGLD and KMCK through the TAF period. Winds will shift from the northeast to the southeast, then to the south as a warm front lifts over the region. Thunderstorms are expected to develop and spread northeast this afternoon and overnight tonight. A few storms are possible at KGLD, however confidence was too low to include mention. Better chances will be at KMCK late this evening and early Tuesday morning. VCTS group was included at KMCK during period highlighted by majority of guidance. Developing LLJ will result in a period of low level wind shear after 06Z through sunrise. && .GLD Watches/Warnings/Advisories... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...JBH AVIATION...DR
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
1229 PM CDT MON JUL 18 2016 ...Update to aviation forecast discussion... .SHORT TERM...(Today and Tonight) Issued at 313 AM CDT MON JUL 18 2016 An MCS moving through northwest MO has formed an outflow that is currently pushing southwestward towards far northeast KS. A west to southwesterly low level jet is intersecting this outflow, and is responsible for additional storm development in that area. Those storms may backbuild into far northeast KS in the next few hours until the cold pool quits progressing or mixes out. There is also increasing isentropic lift taking place in central KS. Storms have formed along this axis of lift that stretches back into southwest KS. The NAM shows this isentropic lift on the 310 K surface nosing into northeast KS in the next few hours with the coverage most likely staying isolated to scattered. Therefore have kept slight chances across the northwest portions of the forecast area through just after sunrise. How far east these showers and storms extend is uncertain at this time. Several consecutive runs of the HRRR have shown this activity reaching east central KS before it weakens as the low level jet decreases. Given the HRRR is already off on storm location means perhaps it might not get far into the forecast area all together. Soundings show about 1500-2000 j/kg of mucape above drier air in the lower levels and a weak nocturnal inversion. The effective shear is also around 30 kt, which is marginal from organization. If a storm were to realize this instability perhaps a strong localized wind gust could not be ruled out within the stronger cells. Later today the temperatures will warm again into the mid 90s to lower 100s with dew points in the upper 60s to lower 70s. This combination will cause heat indices between 100-105 this afternoon, and a heat advisory is in effect. .LONG TERM...(Tuesday through Sunday) Issued at 313 AM CDT MON JUL 18 2016 Heat indicies continue their climb through the week, with Tuesday bringing another day in the 100-105 range, followed by a jump into the 103-109 range by Wednesday and continuing in that range into Friday. As a result, and in collaboration with neighbor offices, have opted to carry a heat advisory through the week. With several days of heat indicies above 100 by mid week, may need to upgrade to a warning for the mid to late week time period, considering the cumulative impacts of several days of heat. In short, outdoor activities this week will require vigilance about the potential impacts of several days of heat advisories. Please plan accordingly. EC and GFS both try to break down the ridge through the weekend as an upper trof progresses across the US/Canadian border and sends a front southward in its wake. EC is stronger and farther southward with the upper trof, and therefore faster moving the boundary into southern Kansas by late Saturday. The GFS has a slower progression but does bring the front through on Sunday. Sensible weather impacts would be an increasing chance for rain into Sunday, and a break from the heat of the week. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday Afternoon) Issued at 1227 PM CDT MON JUL 18 2016 For the 18Z TAFs, expect VFR conditions to prevail throughout the period. Winds should slowly veer to a more SSE component into the afternoon and evening. Slightly stronger winds near KMHK until around the 01Z time frame. && .TOP Watches/Warnings/Advisories... Heat Advisory until 7 PM CDT Friday for KSZ008>012-020>024-026- 034>040-054>056-058-059. && $$ SHORT TERM...Sanders LONG TERM...67 AVIATION...Drake
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
614 AM CDT MON JUL 18 2016 ...Update to aviation forecast discussion... .SHORT TERM...(Today and Tonight) Issued at 313 AM CDT MON JUL 18 2016 An MCS moving through northwest MO has formed an outflow that is currently pushing southwestward towards far northeast KS. A west to southwesterly low level jet is intersecting this outflow, and is responsible for additional storm development in that area. Those storms may backbuild into far northeast KS in the next few hours until the cold pool quits progressing or mixes out. There is also increasing isentropic lift taking place in central KS. Storms have formed along this axis of lift that stretches back into southwest KS. The NAM shows this isentropic lift on the 310 K surface nosing into northeast KS in the next few hours with the coverage most likely staying isolated to scattered. Therefore have kept slight chances across the northwest portions of the forecast area through just after sunrise. How far east these showers and storms extend is uncertain at this time. Several consecutive runs of the HRRR have shown this activity reaching east central KS before it weakens as the low level jet decreases. Given the HRRR is already off on storm location means perhaps it might not get far into the forecast area all together. Soundings show about 1500-2000 j/kg of mucape above drier air in the lower levels and a weak nocturnal inversion. The effective shear is also around 30 kt, which is marginal from organization. If a storm were to realize this instability perhaps a strong localized wind gust could not be ruled out within the stronger cells. Later today the temperatures will warm again into the mid 90s to lower 100s with dew points in the upper 60s to lower 70s. This combination will cause heat indices between 100-105 this afternoon, and a heat advisory is in effect. .LONG TERM...(Tuesday through Sunday) Issued at 313 AM CDT MON JUL 18 2016 Heat indicies continue their climb through the week, with Tuesday bringing another day in the 100-105 range, followed by a jump into the 103-109 range by Wednesday and continuing in that range into Friday. As a result, and in collaboration with neighbor offices, have opted to carry a heat advisory through the week. With several days of heat indicies above 100 by mid week, may need to upgrade to a warning for the mid to late week time period, considering the cumulative impacts of several days of heat. In short, outdoor activities this week will require vigilance about the potential impacts of several days of heat advisories. Please plan accordingly. EC and GFS both try to break down the ridge through the weekend as an upper trof progresses across the US/Canadian border and sends a front southward in its wake. EC is stronger and farther southward with the upper trof, and therefore faster moving the boundary into southern Kansas by late Saturday. The GFS has a slower progression but does bring the front through on Sunday. Sensible weather impacts would be an increasing chance for rain into Sunday, and a break from the heat of the week. && .AVIATION...(For the 12Z TAFS through 12Z Tuesday Morning) Issued at 612 AM CDT MON JUL 18 2016 VFR conditions expected through the taf period. There may be occasional gusts around 20 mph during the day especially at MHK. && .TOP Watches/Warnings/Advisories... Heat Advisory from 1 PM this afternoon to 7 PM CDT Friday for KSZ008>012-020>024-026-034>040-054>056-058-059. && $$ SHORT TERM...Sanders LONG TERM...67 AVIATION...Sanders
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
330 AM CDT MON JUL 18 2016 .SHORT TERM...(Today and Tonight) Issued at 313 AM CDT MON JUL 18 2016 An MCS moving through northwest MO has formed an outflow that is currently pushing southwestward towards far northeast KS. A west to southwesterly low level jet is intersecting this outflow, and is responsible for additional storm development in that area. Those storms may backbuild into far northeast KS in the next few hours until the cold pool quits progressing or mixes out. There is also increasing isentropic lift taking place in central KS. Storms have formed along this axis of lift that stretches back into southwest KS. The NAM shows this isentropic lift on the 310 K surface nosing into northeast KS in the next few hours with the coverage most likely staying isolated to scattered. Therefore have kept slight chances across the northwest portions of the forecast area through just after sunrise. How far east these showers and storms extend is uncertain at this time. Several consecutive runs of the HRRR have shown this activity reaching east central KS before it weakens as the low level jet decreases. Given the HRRR is already off on storm location means perhaps it might not get far into the forecast area all together. Soundings show about 1500-2000 j/kg of mucape above drier air in the lower levels and a weak nocturnal inversion. The effective shear is also around 30 kt, which is marginal from organization. If a storm were to realize this instability perhaps a strong localized wind gust could not be ruled out within the stronger cells. Later today the temperatures will warm again into the mid 90s to lower 100s with dew points in the upper 60s to lower 70s. This combination will cause heat indices between 100-105 this afternoon, and a heat advisory is in effect. .LONG TERM...(Tuesday through Sunday) Issued at 313 AM CDT MON JUL 18 2016 Heat indicies continue their climb through the week, with Tuesday bringing another day in the 100-105 range, followed by a jump into the 103-109 range by Wednesday and continuing in that range into Friday. As a result, and in collaboration with neighbor offices, have opted to carry a heat advisory through the week. With several days of heat indicies above 100 by mid week, may need to upgrade to a warning for the mid to late week time period, considering the cumulative impacts of several days of heat. In short, outdoor activities this week will require vigilance about the potential impacts of several days of heat advisories. Please plan accordingly. EC and GFS both try to break down the ridge through the weekend as an upper trof progresses across the US/Canadian border and sends a front southward in its wake. EC is stronger and farther southward with the upper trof, and therefore faster moving the boundary into southern Kansas by late Saturday. The GFS has a slower progression but does bring the front through on Sunday. Sensible weather impacts would be an increasing chance for rain into Sunday, and a break from the heat of the week. && .AVIATION...(For the 06Z TAFS through 06Z Monday Night) Issued at 1150 PM CDT SUN JUL 17 2016 VFR conditions are likely through the TAF period. Have winds from 220 degrees in the 34-40 kt range within the 800-1500 foot AGL layer causing LLWS with light southeasterly winds at the sfc. Small chance for shra/tsra mainly between 08Z-13Z, but this chance is very small at TAF sites. && .TOP Watches/Warnings/Advisories... Heat Advisory from 1 PM this afternoon to 7 PM CDT Friday for KSZ008>012-020>024-026-034>040-054>056-058-059. && $$ SHORT TERM...Sanders LONG TERM...67 AVIATION...Barjenbruch Area Forecast Discussion National Weather Service Phoenix AZ 208 AM MST WED JUL 20 2016 .SYNOPSIS... The dry weather across southeast California and southwest Arizona will begin to spread eastward today, with chances for showers and thunderstorms gradually dwindling across central Arizona. By Friday, just low end chances will be confined to Arizona`s higher elevation areas. In response, temperatures will warm up with excessive heat conditions possible Friday. The weather pattern will undergo a transition during the weekend and it is looking possible that a more active pattern will become established next week. && .DISCUSSION... Few showers/thunderstorms moving through central Arizona early this morning, associated with an upper level low who`s swirl can be seen in water vapor and infrared satellite images. Operational HRRR has not handled this feature and resultant precipitation well (just catching on the past few runs) but the HRRR-X is exhibiting much better performance. Based on current trends and HRRR-X forecast, expect shower activity to move north of Maricopa County by around 13 UTC/6 AM MST. For the rest of the day, mix of clouds in the morning should slow warming across central Arizona while southwest Arizona and southeast California enjoy fuller sunshine and quickly warming temperatures. Preponderance of high-res convective allowing models (CAMs) for today keep convection confined to the Rim area to our northwest and sky islands to our south. It does seem possible, especially from the NCAR Ensemble and SPC Storm-Scale of Opportunity Ensemble, that some outflow boundaries will make their way into the Phoenix area again this evening and perhaps touch of a few showers/storms. As usual, chance of outflows exceed chance of rain. This seems reasonable given a mixed boundary layer exceeding 700 mb but modest instability (mixed layer CAPE of around 300 J/kg) and warrants continued low but non- zero chances for precipitation. Further west...airmass remains too dry and stable to support any convection. Moisture really begins to thin out on Thursday as boundary layer mixing ratio values during the afternoon drop to about 8 g/kg or less across our entire CWA. Still a fleeting chance for precipitation as it is possible some lingering moisture could boost instability, but definitely on the downward trend. And as usually is the case for our climate this time of year, if the moisture decreases the temperatures take advantage. GFS/EC and GEFS point to 850 mb temperatures climbing to around 32C for Friday, which will yield high temperatures in the 110-115 range for the lower elevations. Given modest remnant moisture and perhaps nocturnal debris clouds, low temperatures at-or-above 90F seem quite likely Friday and Saturday mornings. Given these high end temperatures, we are issuing an Excessive Heat Watch for Friday focusing on the Phoenix area where the urban infrastructure will boost overnight lows. At this point it appears to be a marginal event, and confidence is moderate at this time for excessive heat conditions to come to fruition (hence issuance of a watch, which is not a guarantee by itself of course but highlight the enhanced risk). There is certainly plausible scenarios where excessive heat conditions persist into Saturday (or even develop early on Thursday). As the weekend progresses, the upper level (250 mb) flow pattern will be adjusting. The heat dome parked over the central CONUS today will be migrating southwest through Saturday (hence our heat event), but will become suppressed and weaken Sunday as a trough moves across the northern tier states. The southern edge of that trough appears as if it will develop into a shear axis that extends from near southern California into the Central Plains by the middle of next week. With a strong upper level anti-cyclone to our northwest, the cloud-bearing flow across Arizona will become much more easterly. Winds in the 700-500 mb layer will be 10-20 kt and propagation/Corfidi vectors will also be near 20 kt, all with an easterly flow. At the same time, appears the Sierra Madre will be lighting up with thunderstorms by next week, which is a great pumping mechanism to transport moisture into the Sonora Desert. This all points to the potential for a more active thunderstorm period beginning Tuesday and, should the heart of the 500 mb anti-cyclone stay in a preferred location to our north, continuing for well beyond our forecast period. && .AVIATION... South-Central Arizona Including KPHX, KIWA, and KSDL: Will continue to see showers and thunderstorms mainly east of the Phoenix area this evening, but we may see showers or thunderstorms affect area terminals mainly between midnight and 6am. Not anticipating any more gusty outflow winds tonight, but if under a storm winds could still be gusty. Will keep VCSH in TAFS tonight as I feel there is still a somewhat good chance of showers affecting the Phoenix area. Winds will keep an easterly heading through at least noon before switching to upslope westerlies. Will again see another chance of showers and thunderstorms for Wednesday evening which may include gusty outflow winds and the possibility of more blowing dust. Confidence at this point is too low to actually include in area TAFS. Southeast California/Southwest Arizona including KIPL and KBLH: Little aviation concerns through with storm activity well off to the east into central Arizona. Expect mostly clear skies and southerly winds into tomorrow. Aviation Discussion not updated for amended TAFs. && .FIRE WEATHER... Friday through Tuesday...Temperatures will trend back into an above normal range through the weekend as moisture levels thin and humidity values drop. Thunderstorm/wetting rain chances dwindle and become mostly limited to the higher terrain of eastern Arizona by Friday and Saturday. Consequently, afternoon humidity levels will drop into the 10-25 percent range this weekend. Outside of any thunderstorms, winds will be typical with some afternoon gustiness. && .SPOTTER INFORMATION STATEMENT... Spotter activation may be required for this evening. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...Excessive Heat Watch from late Thursday night through Friday evening for AZZ023. CA...None. && $$ Visit us on Facebook...Twitter...and at weather.gov/phoenix DISCUSSION...Iniguez AVIATION...Kuhlman FIRE WEATHER...Deemer/Iniguez
AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
227 AM PDT WED JUL 20 2016 .SYNOPSIS... It will be hot through the period. The hottest days will be Friday and Saturday. && .SHORT TERM...(TDY-FRI) Not much to say that has not already been said. Srn CA is on track for 7 days of heat with the likely peak occuring on Friday and Saturday. Large hot CONUS spanning upper high centered over Oklahoma will expand westward today and tomorrow. For Friday and Saturday a secondary upper high will pinch off form the main one and sit atop of the state. There will be weak onshore flow to the east but from the north there will be actual offshore flow from north in the morning shifting to weak onshore in the afternoon. Max temps will push up a degree or two today through Friday and then hold pretty steady on Saturday. Max temps will be above normal across the area. The beach and near coast areas will see max temps 2 to 4 degrees above normal...The mountains and the interior vlys will be 3 to 6 degrees above normal...but its the vlys that will really see the heat with max temps 8 to 12 degrees above normal. Records are very high for this period and while it will be warm it will not be record breaking heat. Also of concern will be the low temps which may struggle to fall below 70 degrees across many vly locations. There is not much humidity with this event so the heat index values will not reach into the danger zone so heat warnings do not look too likely...but people will have to take care in the heat esp in the afternoons. Mdls hint at some offshore winds for the central coast each morning. The mdls more often than not over do these winds but if they do develop the central coast cities will have max temps in the 90s that occur around 11 am with quick cooling occuring in the afternoon. Marine layer stratus will be patchy at best and if it does form it will only affect the Long Beach LAX area and the Lompoc Santa Maria area. Skies will be partly cloudy at times today and Thursday as high level clouds from Tropical Storm Estelle blow off and then move over Srn Ca. There will be sundowners each night through Friday night across the SBA south coast. The strongest will be tonight and Thursday night. Low end wind advisories will likely be needed. Hard to see temps getting much below 80 degrees near the gustier canyons. Right now no mdl is transporting any monsoon moisture into the area and the mtns should remain convection free through the period. .LONG TERM...(SAT-TUE) Both the EC and the GFS agree that some sort of very hot upper high will stick around the CA/NV area through the extended period. The mdls show better onshore flow developing so this will bring a better and earlier sea breeze which will result in some cooling for the coasts and vlys. It looks like the Antelope Vly will have the same 104 degree readings for the entire period. Have some marine layer clouds into the forecast for the coasts which is possible given the increase in onshore flow but it is not a slam dunk by any means. There might be a better chc of some monsoon moisture moving in Sunday and more so Monday and Tuesday but still to early to tease out the fine details like that. && .AVIATION... 20/0530Z At 0515Z at KLAX the marine layer depth was around 700 feet deep. The top of the inversion was around 2300 feet with a temperature of 28 degrees Celsius. Very good confidence in all TAFs except for KSBP and KLAX where there is 40 percent chc of IFR cigs 11Z to 17Z and KSMX and KLGB where there is 40 percent chc of no cigs. KLAX...Low confidence in TAF from 11Z-17Z where there is a 40 percent chc of IFR cigs. Good confidence for the rest of the TAF period. KBUR...Very Good confidence in 06Z TAF. && .MARINE... 20/200 AM For the Outer Waters, high confidence in the current forecast. Gusty northwest winds will continue through Sunday. The current Small Craft Advisory has been extended through Thursday evening and will likely need to be extended through the weekend by future shifts. For Friday and Saturday, there is a chance that the northwest gusts could reach gale levels and a Gale Watch may be needed. For the Inner Waters, moderate to high confidence in the current forecast. For the waters north of Point Sal, gusty northwest winds are expected each afternoon/evening through Saturday. A Small Craft Advisory has been issued for this afternoon/evening and will likely be needed for the same time periods Thursday through Saturday. For the waters south of Point Conception, winds are generally expected to remain below Small Craft Advisory levels through the weekend. The only exception will be the western half of the Santa Barbara Channel where there is a good chance of gusts reaching Small Craft Advisory levels in the afternoon/evening hours Thursday and Friday. && .BEACHES... 19/200 PM A beach hazards statement has been issued for south and southwest facing beaches for late this afternoon and tonight due to elevated surf and a high risk of rip currents. There is a possibility of minor tidal overflow during the evening high tide around 830 pm tonight. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Beach Hazards Statement in effect until 3 AM PDT early this morning For zones 40-41-87. (See LAXCFWLOX). PZ...Small Craft Advisory in effect from noon today to 9 PM PDT this evening For zone 645. (See LAXMWWLOX). Small Craft Advisory in effect until 9 PM PDT Thursday For zones 670-673-676. (See LAXMWWLOX). && $$ PUBLIC...Rorke AVIATION...Rorke MARINE...RAT BEACHES...Hall SYNOPSIS...Seto weather.gov/losangeles
  [top] Area Forecast Discussion National Weather Service Sacramento CA 216 AM PDT WED JUL 20 2016 .SYNOPSIS... Dry with below normal temperatures today and Thursday as a low pressure system moves northeast through the Pacific Northwest. Warming Friday then above normal temperatures over the weekend as high pressure pushes westward over the region. Above normal temperatures continuing through the middle of next week. && .DISCUSSION... Northern California remains under dry stable southwest flow aloft between a trough of low pressure over the eastern Pacific and a large high over the central U.S. Relatively cool airmass and onshore flow will keep daytime highs a few to several degrees cooler than normal today. Temperatures are running about the same or slightly warmer than 24 hours ago. Delta breeze is slightly less this morning and expected to be a little weaker today now that a shortwave trough has passed on its way through far Norcal. Marine layer about as deep as yesterday morning with only patchy stratus near the coast so at most just a touch of status could make it into western Solano county today and Thursday mornings. Some areas may see a slight warming today but overall little change is expected from Tuesday temperatures. The eastern Pacific trough is forecast by models to shift into the Pacific Northwest on Thursday and Thursday night. This will allow for a little warming as upper ridging over the southwest U.S is allowed to push back over the west. Only a slight increase in temperatures is expected however with daily highs remaining a few to several degrees below normal. Flat high pressure establishes itself over the state by Friday bringing continued dry and stable conditions with daytime highs back up close to normal for this time of year. As upper ridge centers over the west coast on Saturday...overall airmass warms with highs bumping up above normal going into the weekend. && .EXTENDED DISCUSSION (Sunday THROUGH Wednesday) Warm weather and dry conditions on tap for next week as high pressure remains in control. Delta Breeze will bring limited cooling to nearby areas with ridge overhead. Temperatures will be above normal thru the period with Valley highs in the 98-105 degree range and 80s/90s across higher elevations. CEO && .AVIATION... VFR conditions with onshore winds around 10 kts. Gusts to 20-25kts invof of the Delta. && .STO Watches/Warnings/Advisories... None. && $$
  [top] Area Forecast Discussion National Weather Service Phoenix AZ 208 AM MST WED JUL 20 2016 .SYNOPSIS... The dry weather across southeast California and southwest Arizona will begin to spread eastward today, with chances for showers and thunderstorms gradually dwindling across central Arizona. By Friday, just low end chances will be confined to Arizona`s higher elevation areas. In response, temperatures will warm up with excessive heat conditions possible Friday. The weather pattern will undergo a transition during the weekend and it is looking possible that a more active pattern will become established next week. && .DISCUSSION... Few showers/thunderstorms moving through central Arizona early this morning, associated with an upper level low who`s swirl can be seen in water vapor and infrared satellite images. Operational HRRR has not handled this feature and resultant precipitation well (just catching on the past few runs) but the HRRR-X is exhibiting much better performance. Based on current trends and HRRR-X forecast, expect shower activity to move north of Maricopa County by around 13 UTC/6 AM MST. For the rest of the day, mix of clouds in the morning should slow warming across central Arizona while southwest Arizona and southeast California enjoy fuller sunshine and quickly warming temperatures. Preponderance of high-res convective allowing models (CAMs) for today keep convection confined to the Rim area to our northwest and sky islands to our south. It does seem possible, especially from the NCAR Ensemble and SPC Storm-Scale of Opportunity Ensemble, that some outflow boundaries will make their way into the Phoenix area again this evening and perhaps touch of a few showers/storms. As usual, chance of outflows exceed chance of rain. This seems reasonable given a mixed boundary layer exceeding 700 mb but modest instability (mixed layer CAPE of around 300 J/kg) and warrants continued low but non- zero chances for precipitation. Further west...airmass remains too dry and stable to support any convection. Moisture really begins to thin out on Thursday as boundary layer mixing ratio values during the afternoon drop to about 8 g/kg or less across our entire CWA. Still a fleeting chance for precipitation as it is possible some lingering moisture could boost instability, but definitely on the downward trend. And as usually is the case for our climate this time of year, if the moisture decreases the temperatures take advantage. GFS/EC and GEFS point to 850 mb temperatures climbing to around 32C for Friday, which will yield high temperatures in the 110-115 range for the lower elevations. Given modest remnant moisture and perhaps nocturnal debris clouds, low temperatures at-or-above 90F seem quite likely Friday and Saturday mornings. Given these high end temperatures, we are issuing an Excessive Heat Watch for Friday focusing on the Phoenix area where the urban infrastructure will boost overnight lows. At this point it appears to be a marginal event, and confidence is moderate at this time for excessive heat conditions to come to fruition (hence issuance of a watch, which is not a guarantee by itself of course but highlight the enhanced risk). There is certainly plausible scenarios where excessive heat conditions persist into Saturday (or even develop early on Thursday). As the weekend progresses, the upper level (250 mb) flow pattern will be adjusting. The heat dome parked over the central CONUS today will be migrating southwest through Saturday (hence our heat event), but will become suppressed and weaken Sunday as a trough moves across the northern tier states. The southern edge of that trough appears as if it will develop into a shear axis that extends from near southern California into the Central Plains by the middle of next week. With a strong upper level anti-cyclone to our northwest, the cloud-bearing flow across Arizona will become much more easterly. Winds in the 700-500 mb layer will be 10-20 kt and propagation/Corfidi vectors will also be near 20 kt, all with an easterly flow. At the same time, appears the Sierra Madre will be lighting up with thunderstorms by next week, which is a great pumping mechanism to transport moisture into the Sonora Desert. This all points to the potential for a more active thunderstorm period beginning Tuesday and, should the heart of the 500 mb anti-cyclone stay in a preferred location to our north, continuing for well beyond our forecast period. && .AVIATION... South-Central Arizona Including KPHX, KIWA, and KSDL: Will continue to see showers and thunderstorms mainly east of the Phoenix area this evening, but we may see showers or thunderstorms affect area terminals mainly between midnight and 6am. Not anticipating any more gusty outflow winds tonight, but if under a storm winds could still be gusty. Will keep VCSH in TAFS tonight as I feel there is still a somewhat good chance of showers affecting the Phoenix area. Winds will keep an easterly heading through at least noon before switching to upslope westerlies. Will again see another chance of showers and thunderstorms for Wednesday evening which may include gusty outflow winds and the possibility of more blowing dust. Confidence at this point is too low to actually include in area TAFS. Southeast California/Southwest Arizona including KIPL and KBLH: Little aviation concerns through with storm activity well off to the east into central Arizona. Expect mostly clear skies and southerly winds into tomorrow. Aviation Discussion not updated for amended TAFs. && .FIRE WEATHER... Friday through Tuesday...Temperatures will trend back into an above normal range through the weekend as moisture levels thin and humidity values drop. Thunderstorm/wetting rain chances dwindle and become mostly limited to the higher terrain of eastern Arizona by Friday and Saturday. Consequently, afternoon humidity levels will drop into the 10-25 percent range this weekend. Outside of any thunderstorms, winds will be typical with some afternoon gustiness. && .SPOTTER INFORMATION STATEMENT... Spotter activation may be required for this evening. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...Excessive Heat Watch from late Thursday night through Friday evening for AZZ023. CA...None. && $$ Visit us on Facebook...Twitter...and at weather.gov/phoenix DISCUSSION...Iniguez AVIATION...Kuhlman FIRE WEATHER...Deemer/Iniguez
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
251 AM CDT WED JUL 20 2016 .SHORT TERM...(Today and Tonight) Issued at 251 AM CDT WED JUL 20 2016 A warm night tonight with temperatures still near 80 in many locations. A little more southerly wind in past days likely keeping the boundary layer more more mixed than previous nights. Convection tonight is also farther north and west, leaving the forecast area under mostly clear skies at this hour. Temperatures rise a degree or two from yesterdays numbers, with highs in the middle 90s to near 100. Heat indicies running from 100-109F across the area as the excessive heat warning continues. A little more wind today but not likely to make it feel much cooler. Lows tonight fall into the middle 70s to near 80. .LONG TERM...(Thursday through Tuesday) Issued at 251 AM CDT WED JUL 20 2016 Only minor changes to previous forecast. Upper high still in place into the late week before weakening late Friday into the weekend. Southwest low level flow and general subsidence keep the hot conditions in place with little opportunity for precipitation. 850mb temps continue their rise into Thursday and remain fairly steady into Saturday with the main challenges being in the specifics of the air and wet bulb temps. Went on the warmer and drier side of guidance given model performance in recent similar environments. Heat index values still looking to reach 103 to 110 through Saturday. Upper wave passing over the northern states still looks to drag a cold front into the area Saturday night into Sunday for at least cooler temps and some chance for precipitation. Chances should linger into Tuesday as another wave takes a similar track to the north, with isentropic lift resulting. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday Night) Issued at 1123 PM CDT TUE JUL 19 2016 VFR conditions look to prevail due to the upper ridge overhead and LLWS continues to look to marginal to include in the forecast. && .TOP Watches/Warnings/Advisories... Excessive Heat Warning until 7 PM CDT Saturday for KSZ008>012- 020>024-026-034>040-054>056-058-059. && $$ SHORT TERM...67 LONG TERM...65 AVIATION...Wolters
  [top] Area Forecast Discussion National Weather Service Dodge City KS 235 AM CDT WED JUL 20 2016 ...Updated for Short and Long Term... .SHORT TERM...(Today and tonight) Issued at 226 AM CDT Wed Jul 20 2016 For today, the heat continues with upper level warm ridging intact across the Central Plains. High temps will be dependent on 700 mb forecast temps that show not much change from yesterday. However more downslope surface winds will add a few degrees to highs today. Also with downslope and deep mixing, the dewpoints will mix out, so no heat headlines planned today. Highs will range from 101 west of Dodge to near 98 at Dodge City and around 101 from Medicine Lodge to Hays. South to southwest winds increase to 15 to 24 mph in the afternoon with a lee trough and clear skies. For tonight, south winds decrease to around 10 mph with clear skies. Overnight lows will range from around 70 far west near the Colorado border to the mid 70s across south central sections. .LONG TERM...(Thursday through Tuesday) Issued at 226 AM CDT Wed Jul 20 2016 For Thursday and Friday, the heat continues with 700 mb temps warming a few degrees. This will allow mix down temps to be a few degrees warmer and range from 100 to 104. However dewpoints below 65 are expected and likely not add to the heat index. Still these temps will be very close to heat advisory especially for south central sections where dewpoints will be the highest. Later shifts may need evaluate how much dewpoints mix out, and if heat advisories will be required for parts of the area. For the weekend into early next week. Shortwave troughs will traverse across the Plains with increasing chances for mainly late afternoon and evening scattered thunderstorms. These waves will allow the heat wave to break with highs back into the low to mid 90s from Sunday into Tuesday. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) Issued at 1137 PM CDT Tue Jul 19 2016 VFR conditions will prevail with high pressure ridging and a surface lee trough. Light southeast winds become south to southwesterly at 15-24kt after 15Z. LLWS is forecast through 12-15Z with winds off the deck around 40kt. && .PRELIMINARY POINT TEMPS/POPS... DDC 98 74 101 74 / 0 0 0 10 GCK 100 72 101 71 / 0 0 0 10 EHA 98 72 101 71 / 0 0 0 10 LBL 99 73 103 72 / 0 0 0 10 HYS 101 75 102 74 / 0 0 0 10 P28 100 76 102 76 / 0 0 0 0 && .DDC Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Kruse LONG TERM...Kruse AVIATION...Kruse
Area Forecast Discussion National Weather Service Dodge City KS 235 AM CDT WED JUL 20 2016 ...Updated for Short and Long Term... .SHORT TERM...(Today and tonight) Issued at 226 AM CDT Wed Jul 20 2016 For today, the heat continues with upper level warm ridging intact across the Central Plains. High temps will be dependent on 700 mb forecast temps that show not much change from yesterday. However more downslope surface winds will add a few degrees to highs today. Also with downslope and deep mixing, the dewpoints will mix out, so no heat headlines planned today. Highs will range from 101 west of Dodge to near 98 at Dodge City and around 101 from Medicine Lodge to Hays. South to southwest winds increase to 15 to 24 mph in the afternoon with a lee trough and clear skies. For tonight, south winds decrease to around 10 mph with clear skies. Overnight lows will range from around 70 far west near the Colorado border to the mid 70s across south central sections. .LONG TERM...(Thursday through Tuesday) Issued at 226 AM CDT Wed Jul 20 2016 For Thursday and Friday, the heat continues with 700 mb temps warming a few degrees. This will allow mix down temps to be a few degrees warmer and range from 100 to 104. However dewpoints below 65 are expected and likely not add to the heat index. Still these temps will be very close to heat advisory especially for south central sections where dewpoints will be the highest. Later shifts may need evaluate how much dewpoints mix out, and if heat advisories will be required for parts of the area. For the weekend into early next week. Shortwave troughs will traverse across the Plains with increasing chances for mainly late afternoon and evening scattered thunderstorms. These waves will allow the heat wave to break with highs back into the low to mid 90s from Sunday into Tuesday. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) Issued at 1137 PM CDT Tue Jul 19 2016 VFR conditions will prevail with high pressure ridging and a surface lee trough. Light southeast winds become south to southwesterly at 15-24kt after 15Z. LLWS is forecast through 12-15Z with winds off the deck around 40kt. && .PRELIMINARY POINT TEMPS/POPS... DDC 98 74 101 74 / 0 0 0 10 GCK 100 72 101 71 / 0 0 0 10 EHA 98 72 101 71 / 0 0 0 10 LBL 99 73 103 72 / 0 0 0 10 HYS 101 75 102 74 / 0 0 0 10 P28 100 76 102 76 / 0 0 0 0 && .DDC Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Kruse LONG TERM...Kruse AVIATION...Kruse
  [top] Area Forecast Discussion National Weather Service Wichita KS 1200 AM CDT WED JUL 20 2016 .SYNOPSIS... Issued at 303 PM CDT Tue Jul 19 2016 Upper ridging continues to build over the central/southern Plains with shortwave energy coming onshore over the Pacific NW. Meanwhile, another shortwave trough is tracking over eastern Quebec. At the surface, high pressure is centered over the Great Lakes region with weak lee troughing over eastern CO/western Nebraska. && .SHORT TERM...(This evening through Friday night) Issued at 303 PM CDT Tue Jul 19 2016 Upper ridging will continue to strengthen over the central/southern Plains through Thu with 850mb temps warming into the 25-30C range. We should start to see numerous sites get into the low 100s starting Wed and continuing through Fri. Will maintain heat headlines through Fri but with dewpoints mixing out a bit more each day, still feel confident that we are not looking at 110 degree heat indices. In addition, gusty south and southwest winds will also help provide some relief. As mid level temps and associated capping continue to increase, should see a decrease in MCS activity through Fri over the central Plains, so confidence is high in keeping a dry forecast going. .LONG TERM...(Saturday through Tuesday) Issued at 303 PM CDT Tue Jul 19 2016 Both ECMWF and GFS agree in tracking a shortwave across the northern Rockies and into the northern Plains by Sat afternoon. This should help break down the upper ridging over the southern Rockies into the Plains. There is also some agreement in a front trying to make its way down into northern/western KS by late Sat afternoon. So will start to slowly bring storm chances back Sat for parts of central KS and area wide by Sun. However, not confident enough at this point to go with anything higher than a slight chance due to lack of larger scale forcing. As far as temps go, they look to moderate back closer to seasonal normals by Sun. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) Issued at 1158 PM CDT Tue Jul 19 2016 VFR conditions are forecast at all sites throughout the period. Winds should increase in the morning with cumulus redeveloping at most locations. -Howerton && .PRELIMINARY POINT TEMPS/POPS... Wichita-KICT 76 100 76 102 / 0 0 0 0 Hutchinson 75 100 76 103 / 0 0 0 10 Newton 75 99 76 101 / 0 0 0 0 ElDorado 75 97 76 99 / 0 0 0 0 Winfield-KWLD 76 98 76 100 / 0 0 0 0 Russell 74 102 75 104 / 0 0 0 10 Great Bend 74 101 75 104 / 0 0 0 10 Salina 76 101 77 103 / 0 0 0 0 McPherson 75 100 76 103 / 0 0 0 0 Coffeyville 75 96 75 98 / 20 10 0 0 Chanute 75 95 76 97 / 10 10 0 0 Iola 75 95 76 97 / 10 10 0 0 Parsons-KPPF 75 95 75 98 / 10 10 0 0 && .ICT Watches/Warnings/Advisories... Heat Advisory until 8 PM CDT Friday for KSZ051-068-069-083- 092>096-098>100. Heat Advisory from noon Wednesday to 8 PM CDT Friday for KSZ033- 048-050-067-082-091. Excessive Heat Warning until 8 PM CDT Friday for KSZ049-052-053- 070>072. && $$ SHORT TERM...RBL LONG TERM...RBL AVIATION...ADK
Area Forecast Discussion National Weather Service Dodge City KS 1140 PM CDT TUE JUL 19 2016 ...Updated for Aviation... .SHORT TERM...(This evening through Wednesday) Issued at 1223 PM CDT Tue Jul 19 2016 There isn`t much to say, once the upper high takes over. Upper high centered near the Ozarks into Oklahoma this afternoon, with anvil debris from last night`s MCS in Nebraska trapped in the anticyclonic circulation aloft. Between the dissipating cirrus, a lack of a good downslope component, and continued green vegetation/transpiration and high dewpoints, most locales will fall short of 100 again this afternoon. Wednesday...No change in the pattern means no change in the weather. Hot and dry. Models warm 850 mb temps on average another 2 degrees on Wednesday, and with a decent SWly surface wind component gusting near 30 mph, more locations will crack the 100 degree mark. .LONG TERM...(Wednesday night through Tuesday) Issued at 225 PM CDT Tue Jul 19 2016 Strong high pressure aloft will deliver three very hot afternoons Thursday, Friday and Saturday. MEX/GFS guidance still looks a bit too hot, but nonetheless, widespread triple digit heat is anticipated across SW KS as 850 mb temperatures max out around 30C. Next several shifts will need to determine the need for a heat advisory during these afternoons, to match our WFO neighbors to our east and north. The apparent temperature (heat index) grids currently indicate only the far SE zones will flirt with advisory criteria (105) for a couple hours Wednesday, followed by about the eastern 1/2 of the CWA near heat advisory criteria Thursday afternoon. Since Wednesday is marginal, will defer to later shifts on a heat advisory for Thursday. Some of our far eastern zones have a forecasted heat index of 107 in the grids Thursday afternoon, so a heat advisory is likely. Widespread subsidence will keep all zones dry on Thursday. Heights gradually lower on Friday, which may be enough for an isolated thunderstorm across the northern zones as 12z ECMWF suggests. High pressure weakens further over the weekend, allowing for a slow reduction in afternoon temperatures and a gradual upswing in thunderstorm coverage. Upper high pressure will be repositioned well west of SW KS starting Saturday, and remain that way through mid week next week. The return of NW flow aloft ensures there will be a chance of a thunderstorm in SW KS each day, as indicated by the CR-init pop grids. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) Issued at 1137 PM CDT Tue Jul 19 2016 VFR conditions will prevail with high pressure ridging and a surface lee trough. Light southeast winds become south to southwesterly at 15-24kt after 15Z. LLWS is forecast through 12-15Z with winds off the deck around 40kt. && .PRELIMINARY POINT TEMPS/POPS... DDC 73 100 74 103 / 0 0 0 10 GCK 71 100 72 102 / 0 0 0 10 EHA 69 101 71 101 / 0 0 0 10 LBL 71 101 71 102 / 0 0 0 10 HYS 73 101 75 103 / 0 0 0 10 P28 74 100 76 104 / 0 0 0 0 && .DDC Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Turner LONG TERM...Turner AVIATION...Kruse
Area Forecast Discussion National Weather Service Goodland KS 1035 PM MDT TUE JUL 19 2016 .SHORT TERM...(This afternoon through Wednesday) Issued at 147 PM MDT Tue Jul 19 2016 Early afternoon WV imagery and RAP upper level analysis show large scale ridge centered over the plains dominating the pattern across the US. Moist monsoonal plume is wrapping around the western extent of ridge into the Rockies. At the surface; low pressure is in place across eastern Colorado with a trough axis extending from northeast Colorado and across northern Kansas. Southwest flow is in place across much of our cwa. This afternoon-Wednesday: Mean storm track remains well west of our CWA with focus mainly in the central Rockies. A few weak shortwaves may try rotating towards the northwest part of our CWA. West and northwest parts of our CWA (near surface trough) also have better chance to see any thunderstorm activity due to weaker CAP and better instability. Further south and east in our CWA guidance shows a stronger CAP and eventually a significant decrease in CAPE as profiles warm and dry out during the afternoon periods. Strongest precip signal in guidance matches with these trends (northwest). A slightly stronger shortwave and shift in trough axis Wednesday (as indicated by some models) may support a few thunderstorms moving a little further east-southeast Wednesday afternoon (far northwest Kansas). Regarding temperatures/heat indices: Air mass aloft is only expected to become warmer and consensus shows highs 2-4F warmer than today. A major question on heat indices is Tds (which may mix lower in our west). As Tds decrease below 60 heat indices actually decrease from ambient temperature. Td recovery during the nighttime periods we will see overnight heat indices in the 68-76 range (minimum) which is quite mild for our CWA. There may be a few counties along western periphery of current heat advisory that remain below "exact" advisory criteria, but it is close enough and considering the very warm nighttime heat indices and several days in a row of the hot temperatures the decision was made to upgrade watch to heat advisory. Consecutive day requirement is not expected to be met for issuance of heat warning at this time, so advisory was favored. .LONG TERM...(Wednesday night through Tuesday) Issued at 213 PM MDT Tue Jul 19 2016 Overall, not much has changed in the long term. Hot temperatures are still the main story in the midterm while precipitation chances persist throughout the extended. Wednesday night through Friday, high pressure dominates the pattern. Above normal temperatures are anticipated with highs from the upper 90s to the low 100s on both Thursday and Friday, with Thursday being the hotter day for most locations. With dewpoint temperatures in the lower 60s, heat indices will be around 105 generally east of a line from Russell Springs, Kansas to Benkelman, Nebraska. This has warranted a heat headline for these locations. As mentioned in the short term discussion, the watch has been upgraded to a heat advisory (beginning Wednesday afternoon) and extended to cover through Friday afternoon. Expect somewhat dry conditions for the majority of the area, with only slight chances for convection each afternoon/evening as monsoonal moisture filters into the region along the western side of the ridge and disturbances pass through the upper flow. Friday night and the weekend, the ridge across the CONUS breaks down as a trough tracks from the Pacific Northwest and across the northern Plains, sending a cold front south. Will see more seasonal temperatures over the weekend. With a boundary nearby, expect thunderstorm chances through the weekend. Early next week, guidance differs on how the pattern develops. Consensus seems to be that the high pressure retreats to the west, bringing more of a west/northwest flow to the region. Some perturbations round the northern side of the high, traveling from the Rockies to the High Plains. This setup generates an opportunity for additional precipitation as the trough impacting the region during the weekend continues to push towards New England. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) Issued at 1030 PM MDT Tue Jul 19 2016 For KGLD and KMCK, vfr conditions expected through the period. Only a few mid and high clouds expected through the period. Winds begin the period from the south to southeast occasionally gusting near 20kts. This continues overnight with a slight veering to the southwest around 10kts or so after 14z. Both terminals will see wind shear in the 07z-12z timeframe. && .GLD Watches/Warnings/Advisories... KS...Heat Advisory from noon Wednesday to 7 PM CDT Friday for KSZ002>004-014>016-028-029. CO...NONE. NE...Heat Advisory from 11 AM MDT /noon CDT/ Wednesday to 6 PM MDT /7 PM CDT/ Friday for NEZ079>081. && $$ SHORT TERM...DR LONG TERM...JBH AVIATION...99
AREA FORECAST DISCUSSION
National Weather Service New Orleans LA
329 AM CDT WED JUL 20 2016 .Discussion... Main focus this week will continue to be impacts from an upper level ridge on the area in terms of temperatures and convection. This feature, centered near the Texas/Oklahoma border, will remain expanded across the entire southern half of the country throughout the week. Shower and thunderstorm coverage is expected to be fairly shunted as a result of high pressure subsidence. Rain chances for today similar to yesterday (20-30%) except meso models suggesting convection will be along and north of I-12 vs southwestern portions of the CWA as they were yesterday. Thinking timing will be similar to yesterday with most convection in the late morning to early afternoon then cutting off as the afternoon progresses. Temperatures will once again be a few degrees above normal. The current fcst max temps are at to slightly above MAV guidance. Dewpoints starting in the mid 70s should fall mainly into the lower 70s with daytime mixing. The timing of rising temps and falling dewpoints should keep heat indicies just below the 108 heat advisory criteria today. Thursday and Friday will be very similar from temp and pop perspective which is no surprise as the upper level pattern will for all intents and purposes be the same. The ridge will begin to weaken through the weekend and become more of a zonal pattern as a northern stream trough races along the US/Canada border. Temperatures will begin to fall back closer to normal and pops will increase more into the chance category. MEFFER && .AVIATION... Will continue VFR for all terminals today with the possibility of a TS being close by today. Any activity that gets started today should move in from the east and northeast. Updates may be needed during the day for one or two terminals. But conditions should be VFR for most sites through the 12z cycle. && .MARINE... Surface ridge extending westward across the northern gulf will keep winds generally east in the 5 to 15 knot range through much of the week. A weak easterly wave moving through the gulf today may be able to help a few sh/ts develop through the day. The strong upper/mid level ridge over the West is moving into the south-central conus. This upper/mid level high should be able to suppress most sh/ts activity by Thursday. This should hold through the weekend. The surface high will cause the local wind regime to be quite light at less than 10 knots and likely variable at times in direction. && .PRELIMINARY POINT TEMPS/POPS... MCB 95 76 96 75 / 30 10 20 10 BTR 96 77 96 77 / 20 10 30 10 ASD 95 78 94 78 / 30 10 20 10 MSY 94 79 95 79 / 20 10 20 10 GPT 95 78 93 78 / 30 10 20 10 PQL 92 74 93 74 / 30 10 20 10 && .LIX Watches/Warnings/Advisories... LA...None. GM...None. MS...None. GM...None. && $$
  [top] Area Forecast Discussion National Weather Service Shreveport LA 315 AM CDT WED JUL 20 2016 .DISCUSSION... An upper level high pressure system continues to be the main story early this morning, as it dominates across west TX, the Central Plains and the lower Mississippi Valley. The HRRR insists that isolated showers and thunderstorms will develop by late this morning across portions of Southwest AR, likely due to lingering outflow boundaries from yesterdays convection. Can not rule this out and therefore inserted slight chance pops across the aforementioned area. This aftn with the onset of daytime destabilization, additional isolated convection are possible particularly across North Louisiana, Southeast OK, Southwest AR and extreme East TX where highest PWATS will reside /PWATS aoa 2.00 inches/. Sparse diurnally driven precip is anticipated for the remainder of this week, but the main story will be the heat. Lack of widespread beneficial rainfall in recent weeks coupled with an upslope sfc regime, and the 500 mb UL ridge nearing 600 dam suggests temps having the ability to warm into the upper 90s today to the upper 90s and lower triple digit readings by the end of this week. This will push heat indices into the 105-109 degree range CWA-wide, with a few locales equating 110 degrees thus almost nearing Excessive Heat criteria /ex. KMLU heat index equated 110 degrees yesterday aftn/. The Heat Advisory in effect through 7 pm CDT tomorrow is definitely valid but as we have been doing the last few days, we may need to extend the advisory to include Friday. Thereafter, long term solutions continue to show the UL ridge weakening whilst drifting a bit Northward with the center noted near the Four-Corners region. This may open the door for disturbances once confined to the Northern CONUS to near the region, as well as Easterly waves from the Atlantic and Gulf to impinge on the region by early next week. All in all, this unsettled wx pattern could lead to increasing chances for rainfall. The Super-blended solution slight chance to low end chance pops early next week seems valid attm. If this does indeed come into fruition, the increased cloud cover could lead to slightly lowered /albeit still warm/ daytime temps /middle to upper 90s/ which may negate the need for a Heat Advisory next week. Keep in mind, things could change so be sure to stay tuned to the latest wx information. && .PRELIMINARY POINT TEMPS/POPS... SHV 98 79 99 79 / 20 10 10 10 MLU 98 78 99 77 / 20 10 20 10 DEQ 98 76 97 76 / 20 10 10 0 TXK 97 78 98 78 / 20 10 10 0 ELD 96 77 98 77 / 20 10 20 10 TYR 99 78 99 78 / 10 10 10 0 GGG 98 78 99 77 / 10 10 10 0 LFK 96 77 97 76 / 20 10 20 10 && .SHV Watches/Warnings/Advisories... AR...Heat Advisory until 7 PM CDT Thursday for ARZ050-051-059>061- 070>073. LA...Heat Advisory until 7 PM CDT Thursday for LAZ001>006-010>014- 017>022. OK...Heat Advisory until 7 PM CDT Thursday for OKZ077. TX...Heat Advisory until 7 PM CDT Thursday for TXZ096-097-108>112- 124>126-136>138-149>153-165>167. && $$ 29 Area Forecast Discussion National Weather Service Phoenix AZ 835 AM MST WED JUL 20 2016 .SYNOPSIS... The dry weather across southeast California and southwest Arizona will begin to spread eastward today, with chances for showers and thunderstorms gradually dwindling across central Arizona. By Friday, just low end chances will be confined to Arizona`s higher elevation areas. In response, temperatures will warm up with excessive heat conditions possible Friday. The weather pattern will undergo a transition during the weekend and it is looking possible that a more active pattern will become established next week. && .DISCUSSION... After looking at the regional weather balloon soundings we were nearly bug-eyed to see the Arizona monsoon moisture boundary had accelerated north overnight, to Grand Junction Colorado (GJT)? Just curious to see if this was an early start to the southwest and south central Colorado monsoon, but after perusing their upper air sounding climatology (available at SPC), its happened before in mid July. However todays GJT precip water value was climatologically high and roughly in the 95th percentile for the day at 1.19 inches. Monsoon moisture was drawn north with the help of an unseasonably large scale trof struggling to work its way onto the Pacific northwest coast. Back to Arizona. Upper air data showed monsoon moisture was firmly entrenched over most of AZ. Monsoon moisture was not excessive, but not minimal either. And a couple of regional AZ differences with regards to afternoon instability, gleaned from the sounding data, showed convective trigger temperatures over south central were still relatively low, 102 deg F in Phoenix and 91 in Globe/Miami. Highs forecast for today are 108 and 97 degrees respectively. However in southeast AZ, convective trigger temps were higher (again based on their morning weather balloon sounding and just for relative comparison), at 103 degree F. Tucsons high forecast for today is 102. Therefore the regional difference by comparison was, it was a little more stable in southeast AZ than in south central AZ. No worries though because... most important of all was the inverted trof (IT) that came out of Chihuahua Mexico, north into southeast and south central AZ late yesterday afternoon and night, had decayed significantly and was seen working its way into northern AZ this morning. Earlier this feature produced a few showers and thunderstorms in the Phoenix area after midnight. Despite appreciable monsoon moisture over AZ, most convective activity should develop north of our forecast area, generally over the Mogollon Rim and points north. The combination of a weak upper level shortwave moving into northern AZ from southwest AZ, and accelerating upper level winds (speed divergence) flowing into a persistent Jetstream maximum in Utah (again resulting from the slow moving Pacific Northwest trof) will help to divert most of todays storms north. Therefore in south central AZ, including Phoenix, we should be back to the low grade monsoon, meaning a slight chance of afternoon and evening showers and thunderstorms. Ditto on Thursday. Our forecast area portions of southeast CA and southwest AZ will remain relatively dry and hot. Current forecasts look ok for now. No updates planned. .Previous Discussion...330 AM MST... Few showers/thunderstorms moving through central Arizona early this morning, associated with an upper level low who`s swirl can be seen in water vapor and infrared satellite images. Operational HRRR has not handled this feature and resultant precipitation well (just catching on the past few runs) but the HRRR-X is exhibiting much better performance. Based on current trends and HRRR-X forecast, expect shower activity to move north of Maricopa County by around 13 UTC/6 AM MST. For the rest of the day, mix of clouds in the morning should slow warming across central Arizona while southwest Arizona and southeast California enjoy fuller sunshine and quickly warming temperatures. Preponderance of high-res convective allowing models (CAMs) for today keep convection confined to the Rim area to our northwest and sky islands to our south. It does seem possible, especially from the NCAR Ensemble and SPC Storm-Scale of Opportunity Ensemble, that some outflow boundaries will make their way into the Phoenix area again this evening and perhaps touch of a few showers/storms. As usual, chance of outflows exceed chance of rain. This seems reasonable given a mixed boundary layer exceeding 700 mb but modest instability (mixed layer CAPE of around 300 J/kg) and warrants continued low but non- zero chances for precipitation. Further west...airmass remains too dry and stable to support any convection. Moisture really begins to thin out on Thursday as boundary layer mixing ratio values during the afternoon drop to about 8 g/kg or less across our entire CWA. Still a fleeting chance for precipitation as it is possible some lingering moisture could boost instability, but definitely on the downward trend. And as usually is the case for our climate this time of year, if the moisture decreases the temperatures take advantage. GFS/EC and GEFS point to 850 mb temperatures climbing to around 32C for Friday, which will yield high temperatures in the 110-115 range for the lower elevations. Given modest remnant moisture and perhaps nocturnal debris clouds, low temperatures at-or-above 90F seem quite likely Friday and Saturday mornings. Given these high end temperatures, we are issuing an Excessive Heat Watch for Friday focusing on the Phoenix area where the urban infrastructure will boost overnight lows. At this point it appears to be a marginal event, and confidence is moderate at this time for excessive heat conditions to come to fruition (hence issuance of a watch, which is not a guarantee by itself of course but highlight the enhanced risk). There is certainly plausible scenarios where excessive heat conditions persist into Saturday (or even develop early on Thursday). As the weekend progresses, the upper level (250 mb) flow pattern will be adjusting. The heat dome parked over the central CONUS today will be migrating southwest through Saturday (hence our heat event), but will become suppressed and weaken Sunday as a trough moves across the northern tier states. The southern edge of that trough appears as if it will develop into a shear axis that extends from near southern California into the Central Plains by the middle of next week. With a strong upper level anti-cyclone to our northwest, the cloud-bearing flow across Arizona will become much more easterly. Winds in the 700-500 mb layer will be 10-20 kt and propagation/Corfidi vectors will also be near 20 kt, all with an easterly flow. At the same time, appears the Sierra Madre will be lighting up with thunderstorms by next week, which is a great pumping mechanism to transport moisture into the Sonora Desert. This all points to the potential for a more active thunderstorm period beginning Tuesday and, should the heart of the 500 mb anti-cyclone stay in a preferred location to our north, continuing for well beyond our forecast period. && .AVIATION... South-Central Arizona Including KPHX, KIWA, and KSDL: Weather disturbance that led to overnight showers and isolated thunderstorms continued to weaken and move north of the area early this morning and currently expect morning precip to be of the shower variety. Expect scattered to broken mid/high level debris cloud decks into mid morning with most bases aoa 10k feet, with additional clearing by late morning/early afternoon. Another round of convection is possible this evening but due to the showers that already occurred and a stabilized boundary layer, they may be somewhat delayed and not especially vigorous if/when they occur. Will not mention thunder later on in the upcoming TAFs due to low confidence in formation/timing of any storms that do occur. Winds to favor the east this morning, turning to the west by mid afternoon. Should storms occur this evening, gusty outflow winds will likely impact the terminals, probably favoring a south to southeast direction. May see some blowing dust as well but visibilities at the terminals should stay above 3SM. Less convective activity is expected Thursday into Friday as monsoon moisture steadily thins out. Southeast California/Southwest Arizona including KIPL and KBLH: Little aviation concerns through with storm activity well off to the east into central Arizona. Expect mostly clear skies and southerly winds through the day today. Aviation Discussion not updated for amended TAFs. && .FIRE WEATHER... Friday through Tuesday...Temperatures will trend back into a well above normal range through the weekend as moisture levels thin and humidity values drop. Thunderstorm/wetting rain chances dwindle and become mostly limited to the higher terrain of eastern Arizona by Friday and Saturday. Consequently, afternoon humidity levels will fall below 15 percent over the lower deserts through Saturday, and then climb back into the 15-20 percent range Sunday into early next week as thunderstorms chances slowly increase from east to west. Higher RH values are expected across the higher terrain locations. Outside of any thunderstorms, winds will be typical with some afternoon gustiness. && .SPOTTER INFORMATION STATEMENT... Spotter activation may be required for this evening. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...Excessive Heat Watch from late Thursday night through Friday evening for AZZ023. CA...None. && $$ Visit us on Facebook...Twitter...and at weather.gov/phoenix DISCUSSION...Vasquez/Iniguez AVIATION...CB FIRE WEATHER...Deemer/Iniguez/CB
  [top] Area Forecast Discussion National Weather Service Flagstaff AZ 335 AM MST WED JUL 20 2016 .SYNOPSIS...Monsoon moisture will continue to keep showers and thunderstorms in the forecast through at least Thursday. Friday and into the weekend, a drier westerly flow will decrease shower coverage across northwestern Arizona with decent chances for thunderstorms across southern Navajo and Apache counties. && .DISCUSSION...Deep southerly flow continues to import plentiful moisture into the state this morning. A few light showers and an occasional lightning strike were noted at 3 am from around Williams into western Yavapai county and also southern Apache county. Later this morning through the afternoon, expecting another round of showers and thunderstorms, most numerous along the higher terrain though some storms will push northward into some lower terrain areas. Morning cloud cover could play a role in where storms develop first and how strong they become. A mid and upper level disturbance rotating northward across our region today could also act to enhance storm coverage. The main threats today will be locally heavy rainfall and flooding, with some hail and gusty winds with stronger storms as well. Similar conditions are expected Thursday, then a downward trend in moisture and storm activity is forecast starting Friday in the northern part of the state as the ridge axis sinks southward. However, due to the forecast position of the ridge axis, a tight moisture gradient is likely to set up across the area, with higher values of moisture in the southern portion of the forecast area. So we kept a chance of thunderstorms each day into early next week across the Mogollon Rim and White Mountains with generally slight chances elsewhere. There is still some uncertainty with where this moisture gradient sets up, so watch for updated forecasts as the pattern evolves. && .AVIATION...For the 12Z package...Isolated to scattered storms will continue this morning. Look for scattered to numerous SHRA/TSRA to redevelop between 17z-02z today. Brief MVFR/IFR conditions in the stronger storms with locally heavy rain, small hail, and gusty winds. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Scattered to numerous showers and thunderstorms can be expected today and again on Thursday. Storms will generally be moving slowly from south to north. Friday through Sunday...Drier air will start to filter in from the west, which will bring a decrease in thunderstorm activity, especially across the western portion of the state. Minimum RH values will drop back into the teens generally from Flagstaff north. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC...JJ AVIATION...MCS FIRE WEATHER...MCS For Northern Arizona weather information visit weather.gov/flagstaff
Area Forecast Discussion...Updated National Weather Service Phoenix AZ 330 AM MST WED JUL 20 2016 .UPDATE...Updated aviation and fire weather discussions. && .SYNOPSIS... The dry weather across southeast California and southwest Arizona will begin to spread eastward today, with chances for showers and thunderstorms gradually dwindling across central Arizona. By Friday, just low end chances will be confined to Arizona`s higher elevation areas. In response, temperatures will warm up with excessive heat conditions possible Friday. The weather pattern will undergo a transition during the weekend and it is looking possible that a more active pattern will become established next week. && .DISCUSSION... Few showers/thunderstorms moving through central Arizona early this morning, associated with an upper level low who`s swirl can be seen in water vapor and infrared satellite images. Operational HRRR has not handled this feature and resultant precipitation well (just catching on the past few runs) but the HRRR-X is exhibiting much better performance. Based on current trends and HRRR-X forecast, expect shower activity to move north of Maricopa County by around 13 UTC/6 AM MST. For the rest of the day, mix of clouds in the morning should slow warming across central Arizona while southwest Arizona and southeast California enjoy fuller sunshine and quickly warming temperatures. Preponderance of high-res convective allowing models (CAMs) for today keep convection confined to the Rim area to our northwest and sky islands to our south. It does seem possible, especially from the NCAR Ensemble and SPC Storm-Scale of Opportunity Ensemble, that some outflow boundaries will make their way into the Phoenix area again this evening and perhaps touch of a few showers/storms. As usual, chance of outflows exceed chance of rain. This seems reasonable given a mixed boundary layer exceeding 700 mb but modest instability (mixed layer CAPE of around 300 J/kg) and warrants continued low but non- zero chances for precipitation. Further west...airmass remains too dry and stable to support any convection. Moisture really begins to thin out on Thursday as boundary layer mixing ratio values during the afternoon drop to about 8 g/kg or less across our entire CWA. Still a fleeting chance for precipitation as it is possible some lingering moisture could boost instability, but definitely on the downward trend. And as usually is the case for our climate this time of year, if the moisture decreases the temperatures take advantage. GFS/EC and GEFS point to 850 mb temperatures climbing to around 32C for Friday, which will yield high temperatures in the 110-115 range for the lower elevations. Given modest remnant moisture and perhaps nocturnal debris clouds, low temperatures at-or-above 90F seem quite likely Friday and Saturday mornings. Given these high end temperatures, we are issuing an Excessive Heat Watch for Friday focusing on the Phoenix area where the urban infrastructure will boost overnight lows. At this point it appears to be a marginal event, and confidence is moderate at this time for excessive heat conditions to come to fruition (hence issuance of a watch, which is not a guarantee by itself of course but highlight the enhanced risk). There is certainly plausible scenarios where excessive heat conditions persist into Saturday (or even develop early on Thursday). As the weekend progresses, the upper level (250 mb) flow pattern will be adjusting. The heat dome parked over the central CONUS today will be migrating southwest through Saturday (hence our heat event), but will become suppressed and weaken Sunday as a trough moves across the northern tier states. The southern edge of that trough appears as if it will develop into a shear axis that extends from near southern California into the Central Plains by the middle of next week. With a strong upper level anti-cyclone to our northwest, the cloud-bearing flow across Arizona will become much more easterly. Winds in the 700-500 mb layer will be 10-20 kt and propagation/Corfidi vectors will also be near 20 kt, all with an easterly flow. At the same time, appears the Sierra Madre will be lighting up with thunderstorms by next week, which is a great pumping mechanism to transport moisture into the Sonora Desert. This all points to the potential for a more active thunderstorm period beginning Tuesday and, should the heart of the 500 mb anti-cyclone stay in a preferred location to our north, continuing for well beyond our forecast period. && .AVIATION... South-Central Arizona Including KPHX, KIWA, and KSDL: Weather disturbance that led to overnight showers and isolated thunderstorms continued to weaken and move north of the area early this morning and currently expect morning precip to be of the shower variety. Expect scattered to broken mid/high level debris cloud decks into mid morning with most bases aoa 10k feet, with additional clearing by late morning/early afternoon. Another round of convection is possible this evening but due to the showers that already occurred and a stabilized boundary layer, they may be somewhat delayed and not especially vigorous if/when they occur. Will not mention thunder later on in the upcoming TAFs due to low confidence in formation/timing of any storms that do occur. Winds to favor the east this morning, turning to the west by mid afternoon. Should storms occur this evening, gusty outflow winds will likely impact the terminals, probably favoring a south to southeast direction. May see some blowing dust as well but visibilities at the terminals should stay above 3SM. Less convective activity is expected Thursday into Friday as monsoon moisture steadily thins out. Southeast California/Southwest Arizona including KIPL and KBLH: Little aviation concerns through with storm activity well off to the east into central Arizona. Expect mostly clear skies and southerly winds through the day today. Aviation Discussion not updated for amended TAFs. && .FIRE WEATHER... Friday through Tuesday...Temperatures will trend back into a well above normal range through the weekend as moisture levels thin and humidity values drop. Thunderstorm/wetting rain chances dwindle and become mostly limited to the higher terrain of eastern Arizona by Friday and Saturday. Consequently, afternoon humidity levels will fall below 15 percent over the lower deserts through Saturday, and then climb back into the 15-20 percent range Sunday into early next week as thunderstorms chances slowly increase from east to west. Higher RH values are expected across the higher terrain locations. Outside of any thunderstorms, winds will be typical with some afternoon gustiness. && .SPOTTER INFORMATION STATEMENT... Spotter activation may be required for this evening. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...Excessive Heat Watch from late Thursday night through Friday evening for AZZ023. CA...None. && $$ Visit us on Facebook...Twitter...and at weather.gov/phoenix DISCUSSION...Iniguez AVIATION...CB FIRE WEATHER...Deemer/Iniguez/CB
AREA FORECAST DISCUSSION
National Weather Service Eureka CA
506 AM PDT WED JUL 20 2016 .SYNOPSIS...Weather conditions will remain mostly unchanged through the end of the work week. Over the weekend, strong high pressure will bring a significant warming trend, with weekend temperatures approaching the triple digits across the interior persisting into next week. && .DISCUSSION...Typical summer weather continues along the coast with periods of clouds and patchy fog and near normal temperatures. The persistent trough has maintained an onshore flow but has also kept interior temperatures cool and below normal. For the remainder of the week, the trough will finally drift off to the north. As it does so, embedded shortwaves will continue to move through the region, including a particularly vigorous one late on Thursday. As a result, weather conditions will remain relatively static with a slight warming trend through the end of the work week, including the continuation of a deep marine layer and sporadic afternoon/evening showers across our eastern mountains. Coastal areas may also see an increase in overnight/early morning drizzle as well, particularly Thursday morning as the previously mentioned shortwave approaches the coast. By Friday, the last remnants of the stubborn upper trough will drift towards the northeast, allowing an upper level ridge to steadily build across the western United States. Thus folks living or recreating across the interior zones should embrace the cooler weather because by Saturday a substantial warming and drying trend will commence. By this weekend interior valleys will very likely see afternoon highs eclipsing 100 degrees over a broad area, which would be some of the warmest temperatures we`ve seen yet this summer. While it may not be a record-setting heat event, conditions will certainly not be pleasant across the interior valleys. Meanwhile, this will likely speed up the drying of fuels across the region, impacting fire weather conditions down the road. /BRC/JT && .AVIATION...Stratus and patches of fog (FG) or mist (BR) have been slowly redeveloping along the coast and just offshore over the waters early this morning. As of 3AM, KCEC has been down to 1/4SM in fog (FG), while KACV has been unrestricted under light easterly flow. IFR conditions are still expected later this morning at KACV as misty air or low clouds rolls in from the ocean by mid morning. Daytime heating and mixing should scour out most of the stratus this afternoon. VFR conditions with light winds are expected to prevail for the rest of the day at KACV and KCEC, though some patches of IFR may linger through mid afternoon primarily around KCEC. High resolution models continue to indicate higher boundary layer humidities returning tonight and expect conditions to deteriorate once again along the coast. At KUKI, VFR is anticipated through the forecast period. && .MARINE...Northerly winds will gradually increase through the end of the week as high pressure over the central Pacific builds toward the West Coast. Seas will remain mixed with a combination of small NW wind waves and longer period southerly swell. Over the weekend, winds will increase more significantly and large steep northerly waves are anticipated. && .EKA Watches/Warnings/Advisories... CA...None. NORTHWEST CALIFORNIA COASTAL WATERS...None. && $$ 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
  [top] Area Forecast Discussion National Weather Service San Francisco Bay Area 434 AM PDT WED JUL 20 2016 .Synopsis...Patchy low clouds and fog will again linger along the coast mid morning. Otherwise...high pressure building over the region today will begin a warming trend that will extend into the weekend. && .DISCUSSION...as of 03:29 AM PDT Wednesday...A well mixed marine layer continues this morning along the Central California coast this morning. Satellite imagery shows very little in the way of fog development as of 3 am this morning, with exception of a few wisps around the region. However, due to onshore flow and persistent low level moisture fog and low cloud development remains possible this morning. As such, have left the coastal low clouds and fog in the forecast for now, but this may need to be pulled if development does not occur in the next few hours. Broad troughing remains anchored over the NE Pacific this morning. This is maintaining a persistent onshore for the Central California which is keeping a cap on the temperatures. That said, high pressure over West Texas is showing signs of strengthening and is beginning to nose westward. Models continue to indicate this ridge will shift over the four corners regions and into California today into Thursday. This will equate to a slow warming trend for the second half of the week. While near normal temperatures are expected today, look for above normal temps for the weekend. By the weekend models are showing 500 mb heights in the 594 dam range which will yield a strong warming pattern. By the weekend inland areas are expected to reach well into the 90s. Model guidance indicates a weak trough moving across the region late in the weekend which could cap temps in the 90s, but early indications are that the ridge strengthens again next week. This will likely drive inland temps into the 100s. Overall look patchy low clouds and fog along the coast with temperatures on a slow warming trend the next few days. A more substantial warming is expected next week. && .AVIATION...As of 4:35 AM PDT Wednesday...Shallow inversion with dry air aloft limiting widespread stratus development this morning. Latest GOES imagery shows a narrow finger of stratus attempting to develop along the Northern California coastline. This narrow finger is spreading southward this morning and has now reached the Pescadero area and will likely attempt to push southward towards the Monterey Bay into the sunrise hour. Limited inland intrusion expected with spotty MVFR cigs posbl until 15-16Z. Onshore winds this afternoon. Limited return of cigs late tonight. Overall low to moderate confidence. Vicinity of KSFO... MVFR posbl from 12-15/16z. Gusty westerly winds resume Wednesday afternoon and evening. Low to moderate confidence. SFO Bridge Approach...Similar to KSFO. Monterey Bay Terminals...SKC until around sunrise when patchy low cigs possible along the immediate coastline impacting KWVI and possibly KMRY as stratus deck expands southward. Otherwise... VFR today with breezy onshore winds this afternoon. Low to moderate confidence. && .MARINE...as of 04:26 AM PDT Wednesday...Moderate northwest winds will persist through the next several days as high pressure lingers over the eastern pacific. the strongest winds are expected along the immediate coastline... especially along the sonoma and big sur coasts. && .MTR WATCHES/WARNINGS/ADVISORIES... .Tday...SCA...Pigeon Pt to Pt Pinos 0-10 nm from 11 AM SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm SCA...Pt Arena to Pt Reyes 0-10 nm SCA...SF Bay from 2 PM SCA...Mry Bay from 2 PM SCA...Pt Reyes to Pigeon Pt 0-10 nm from 2 PM && $$ PUBLIC FORECAST: BFG AVIATION: DRP MARINE: DRP 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...Updated National Weather Service Phoenix AZ 330 AM MST WED JUL 20 2016 .UPDATE...Updated aviation and fire weather discussions. && .SYNOPSIS... The dry weather across southeast California and southwest Arizona will begin to spread eastward today, with chances for showers and thunderstorms gradually dwindling across central Arizona. By Friday, just low end chances will be confined to Arizona`s higher elevation areas. In response, temperatures will warm up with excessive heat conditions possible Friday. The weather pattern will undergo a transition during the weekend and it is looking possible that a more active pattern will become established next week. && .DISCUSSION... Few showers/thunderstorms moving through central Arizona early this morning, associated with an upper level low who`s swirl can be seen in water vapor and infrared satellite images. Operational HRRR has not handled this feature and resultant precipitation well (just catching on the past few runs) but the HRRR-X is exhibiting much better performance. Based on current trends and HRRR-X forecast, expect shower activity to move north of Maricopa County by around 13 UTC/6 AM MST. For the rest of the day, mix of clouds in the morning should slow warming across central Arizona while southwest Arizona and southeast California enjoy fuller sunshine and quickly warming temperatures. Preponderance of high-res convective allowing models (CAMs) for today keep convection confined to the Rim area to our northwest and sky islands to our south. It does seem possible, especially from the NCAR Ensemble and SPC Storm-Scale of Opportunity Ensemble, that some outflow boundaries will make their way into the Phoenix area again this evening and perhaps touch of a few showers/storms. As usual, chance of outflows exceed chance of rain. This seems reasonable given a mixed boundary layer exceeding 700 mb but modest instability (mixed layer CAPE of around 300 J/kg) and warrants continued low but non- zero chances for precipitation. Further west...airmass remains too dry and stable to support any convection. Moisture really begins to thin out on Thursday as boundary layer mixing ratio values during the afternoon drop to about 8 g/kg or less across our entire CWA. Still a fleeting chance for precipitation as it is possible some lingering moisture could boost instability, but definitely on the downward trend. And as usually is the case for our climate this time of year, if the moisture decreases the temperatures take advantage. GFS/EC and GEFS point to 850 mb temperatures climbing to around 32C for Friday, which will yield high temperatures in the 110-115 range for the lower elevations. Given modest remnant moisture and perhaps nocturnal debris clouds, low temperatures at-or-above 90F seem quite likely Friday and Saturday mornings. Given these high end temperatures, we are issuing an Excessive Heat Watch for Friday focusing on the Phoenix area where the urban infrastructure will boost overnight lows. At this point it appears to be a marginal event, and confidence is moderate at this time for excessive heat conditions to come to fruition (hence issuance of a watch, which is not a guarantee by itself of course but highlight the enhanced risk). There is certainly plausible scenarios where excessive heat conditions persist into Saturday (or even develop early on Thursday). As the weekend progresses, the upper level (250 mb) flow pattern will be adjusting. The heat dome parked over the central CONUS today will be migrating southwest through Saturday (hence our heat event), but will become suppressed and weaken Sunday as a trough moves across the northern tier states. The southern edge of that trough appears as if it will develop into a shear axis that extends from near southern California into the Central Plains by the middle of next week. With a strong upper level anti-cyclone to our northwest, the cloud-bearing flow across Arizona will become much more easterly. Winds in the 700-500 mb layer will be 10-20 kt and propagation/Corfidi vectors will also be near 20 kt, all with an easterly flow. At the same time, appears the Sierra Madre will be lighting up with thunderstorms by next week, which is a great pumping mechanism to transport moisture into the Sonora Desert. This all points to the potential for a more active thunderstorm period beginning Tuesday and, should the heart of the 500 mb anti-cyclone stay in a preferred location to our north, continuing for well beyond our forecast period. && .AVIATION... South-Central Arizona Including KPHX, KIWA, and KSDL: Weather disturbance that led to overnight showers and isolated thunderstorms continued to weaken and move north of the area early this morning and currently expect morning precip to be of the shower variety. Expect scattered to broken mid/high level debris cloud decks into mid morning with most bases aoa 10k feet, with additional clearing by late morning/early afternoon. Another round of convection is possible this evening but due to the showers that already occurred and a stabilized boundary layer, they may be somewhat delayed and not especially vigorous if/when they occur. Will not mention thunder later on in the upcoming TAFs due to low confidence in formation/timing of any storms that do occur. Winds to favor the east this morning, turning to the west by mid afternoon. Should storms occur this evening, gusty outflow winds will likely impact the terminals, probably favoring a south to southeast direction. May see some blowing dust as well but visibilities at the terminals should stay above 3SM. Less convective activity is expected Thursday into Friday as monsoon moisture steadily thins out. Southeast California/Southwest Arizona including KIPL and KBLH: Little aviation concerns through with storm activity well off to the east into central Arizona. Expect mostly clear skies and southerly winds through the day today. Aviation Discussion not updated for amended TAFs. && .FIRE WEATHER... Friday through Tuesday...Temperatures will trend back into a well above normal range through the weekend as moisture levels thin and humidity values drop. Thunderstorm/wetting rain chances dwindle and become mostly limited to the higher terrain of eastern Arizona by Friday and Saturday. Consequently, afternoon humidity levels will fall below 15 percent over the lower deserts through Saturday, and then climb back into the 15-20 percent range Sunday into early next week as thunderstorms chances slowly increase from east to west. Higher RH values are expected across the higher terrain locations. Outside of any thunderstorms, winds will be typical with some afternoon gustiness. && .SPOTTER INFORMATION STATEMENT... Spotter activation may be required for this evening. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...Excessive Heat Watch from late Thursday night through Friday evening for AZZ023. CA...None. && $$ Visit us on Facebook...Twitter...and at weather.gov/phoenix DISCUSSION...Iniguez AVIATION...CB FIRE WEATHER...Deemer/Iniguez/CB Area Forecast Discussion National Weather Service Flagstaff AZ 330 PM MST WED JUL 20 2016 .SYNOPSIS...Showers and thunderstorms will remain in the forecast through tomorrow. A drier westerly flow will decrease shower and thunderstorm coverage across western Arizona Friday into the weekend. Decent chances for thunderstorms will remain across southern Navajo and Apache counties. && .DISCUSSION...Widespread showers and thunderstorms continue across northern Arizona this afternoon. Flash flooding was reported in Oak Creek Canyon and in the Sedona area where flash flood warnings were issued earlier this afternoon. Thunderstorms are just now becoming more widespread across northern Navajo and Apache Counties. While the flash flood threat has ended across much of the area from central Coconino County to central Yavapai County, a heavy rain and possible flood threat will continue elsewhere into the evening hours. Look for storms to diminish after sunset, though northern Navajo and Apache counties could see scattered storms continue until around midnight or so. Another round of showers and thunderstorms is expected across all of northern Arizona tomorrow, beginning after 10AM MST. Storms will initially develop in the higher terrain and slowly work their way to the lower elevations. The main threat with storms tomorrow will once again be very heavy rain due to the slow storm movement, which could lead to localized flash flooding. The stronger storms will also be capable of producing small hail and gusty winds. Beginning Friday, drier air will start to move in from the west. This will reduce storm chances across Coconino and Yavapai Counties. For the weekend, the greatest storm chances will remain over southern Navajo and Apache Counties where the highest moisture remains. && .AVIATION...For the 00Z package...Scattered to numerous showers and thunderstorms will continue before diminishing around 02Z. A few showers will develop overnight. Expect MVFR/IFR conditions in heavy showers. Scattered to numerous thunderstorms will redevelop around Thursday 18Z. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...An active wet Monsoon weather pattern will continue on Thursday with drier air moving into western Arizona on Friday. Drier air will reduce chances for showers and thunderstorms starting on Friday afternoon. Saturday through Monday...A drier low grade Monsoon pattern will remain in the forecast. The highest chances for showers and storms will be across the White Mountains Region. && .FGZ WATCHES/WARNINGS/ADVISORIES...Flash Flood Watch until 8 PM MST this evening FOR AZZ004>008-015- 037-038. && $$ PUBLIC...Mottice AVIATION...Bohlin FIRE WEATHER...Bohlin For Northern Arizona weather information visit weather.gov/flagstaff
  [top] Area Forecast Discussion National Weather Service Tucson AZ 112 PM MST WED JUL 20 2016 .SYNOPSIS...A steady decrease in convection will take place Thursday into the weekend as the air mass over the region dries out. As a result temperatures will climb to roughly 10 degrees warmer than average Friday and Saturday. Monsoon moisture will then gradually return Sunday onward for an overall increase in convection and a slight cooling of afternoon temperatures. && .DISCUSSION...Convection beginning to fire up pretty much as expected to our south with the individual cells moving northward. Expect the activity to increase over the next few hours, primarily south and east of Tucson over higher terrain then spreading north. This all should die off tonight earlier than it has lately with a lack of significant forcing by that time. A steady drying trend kicks in Thursday and especially Friday and Saturday with PWs dropping to around an inch (a bit more south and a bit less north) by Friday and Saturday. This will result in a significant decrease in convection despite a wave sliding by just to our south on Friday. Still carrying some precip chances mainly near the international border where the highest amount of moisture will exist. Afternoon high temperatures will climb through this period peaking Friday and Saturday nearly 10 degrees above normal. Sunday onward the models are suggesting the the upper level ridge will shift slightly north allowing the easterlies to have a greater influence on our area with an increase in moisture. This will help to put us back into the daily rounds of afternoon/evening convection especially if it ends up more like what the ECMWF is suggesting. Will also see a decrease in afternoon high temperatures down a bit closer to average next week. && .AVIATION...VALID THRU 22/00Z. Showers and thunderstorms are developing and will continue through at least 03Z. Storms will be in the vicinity of the terminals, especially KOLS, KTUS, and KSAD through about 01Z. Heavy rainfall, gusty winds, and some areas of blowing dust will be the biggest concerns. The expectation is that storms will begin to wane in coverage after 03Z. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Moisture in place will lead to the daily cycle of mainly afternoon and evening isolated to scattered showers and thunderstorms through Thursday. A drying trend will then lead to reduced coverage of showers and thunderstorms Friday into this weekend. Moisture will remain adequate for isolated to scattered thunderstorms early next week. Outside of gusty thunderstorm outflows, 20-foot winds will be terrain driven and mostly less than 15 mph. && .CLIMATE...Record high temperatures will be approached at a few spots Thursday then most of the area will be at or near record highs Friday and Saturday. && .TWC Watches/Warnings/Advisories... None. && $$ PUBLIC...CERNIGLIA AVIATION....CANTIN FIRE WEATHER...CANTIN Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Area Forecast Discussion National Weather Service Flagstaff AZ 908 AM MST WED JUL 20 2016 .SYNOPSIS...Monsoon moisture will continue to keep showers and thunderstorms in the forecast through at least Thursday. Friday and into the weekend, a drier westerly flow will decrease shower coverage across northwestern Arizona with decent chances for thunderstorms across southern Navajo and Apache counties. && .UPDATE...Clouds cleared out nicely in many locations this morning, which will allow for ample surface heating. Look for storms to develop between 10 and 11 AM MST, first across Yavapai County and the Mogollon Rim, then spreading elsewhere across northern Arizona. Slow storm motion today from south to north will make for a flash flood threat. The stronger storms may also contain small hail and gusty winds. The previous forecast looks good and no significant changes were made. && .PREV DISCUSSION /335 AM MST/...Deep southerly flow continues to import plentiful moisture into the state this morning. A few light showers and an occasional lightning strike were noted at 3 am from around Williams into western Yavapai county and also southern Apache county. Later this morning through the afternoon, expecting another round of showers and thunderstorms, most numerous along the higher terrain though some storms will push northward into some lower terrain areas. Morning cloud cover could play a role in where storms develop first and how strong they become. A mid and upper level disturbance rotating northward across our region today could also act to enhance storm coverage. The main threats today will be locally heavy rainfall and flooding, with some hail and gusty winds with stronger storms as well. Similar conditions are expected Thursday, then a downward trend in moisture and storm activity is forecast starting Friday in the northern part of the state as the ridge axis sinks southward. However, due to the forecast position of the ridge axis, a tight moisture gradient is likely to set up across the area, with higher values of moisture in the southern portion of the forecast area. So we kept a chance of thunderstorms each day into early next week across the Mogollon Rim and White Mountains with generally slight chances elsewhere. There is still some uncertainty with where this moisture gradient sets up, so watch for updated forecasts as the pattern evolves. && .AVIATION...For the 18Z package...Scattered to numerous SHRA/TSRA will redevelop between 18z-02z today. Brief MVFR/IFR conditions in the stronger storms with locally heavy rain, small hail, and gusty winds. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Scattered to numerous showers and thunderstorms can be expected today and again on Thursday. Storms will generally be moving slowly from south to north. Friday through Sunday...Drier air will start to filter in from the west, which will bring a decrease in thunderstorm activity, especially across the western portion of the state. Minimum RH values will drop back into the teens generally from Flagstaff north. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC...Mottice/JJ AVIATION...Mottice FIRE WEATHER...MCS For Northern Arizona weather information visit weather.gov/flagstaff
  [top] Area Forecast Discussion National Weather Service Phoenix AZ 835 AM MST WED JUL 20 2016 .SYNOPSIS... The dry weather across southeast California and southwest Arizona will begin to spread eastward today, with chances for showers and thunderstorms gradually dwindling across central Arizona. By Friday, just low end chances will be confined to Arizona`s higher elevation areas. In response, temperatures will warm up with excessive heat conditions possible Friday. The weather pattern will undergo a transition during the weekend and it is looking possible that a more active pattern will become established next week. && .DISCUSSION... After looking at the regional weather balloon soundings we were nearly bug-eyed to see the Arizona monsoon moisture boundary had accelerated north overnight, to Grand Junction Colorado (GJT)? Just curious to see if this was an early start to the southwest and south central Colorado monsoon, but after perusing their upper air sounding climatology (available at SPC), its happened before in mid July. However todays GJT precip water value was climatologically high and roughly in the 95th percentile for the day at 1.19 inches. Monsoon moisture was drawn north with the help of an unseasonably large scale trof struggling to work its way onto the Pacific northwest coast. Back to Arizona. Upper air data showed monsoon moisture was firmly entrenched over most of AZ. Monsoon moisture was not excessive, but not minimal either. And a couple of regional AZ differences with regards to afternoon instability, gleaned from the sounding data, showed convective trigger temperatures over south central were still relatively low, 102 deg F in Phoenix and 91 in Globe/Miami. Highs forecast for today are 108 and 97 degrees respectively. However in southeast AZ, convective trigger temps were higher (again based on their morning weather balloon sounding and just for relative comparison), at 103 degree F. Tucsons high forecast for today is 102. Therefore the regional difference by comparison was, it was a little more stable in southeast AZ than in south central AZ. No worries though because... most important of all was the inverted trof (IT) that came out of Chihuahua Mexico, north into southeast and south central AZ late yesterday afternoon and night, had decayed significantly and was seen working its way into northern AZ this morning. Earlier this feature produced a few showers and thunderstorms in the Phoenix area after midnight. Despite appreciable monsoon moisture over AZ, most convective activity should develop north of our forecast area, generally over the Mogollon Rim and points north. The combination of a weak upper level shortwave moving into northern AZ from southwest AZ, and accelerating upper level winds (speed divergence) flowing into a persistent Jetstream maximum in Utah (again resulting from the slow moving Pacific Northwest trof) will help to divert most of todays storms north. Therefore in south central AZ, including Phoenix, we should be back to the low grade monsoon, meaning a slight chance of afternoon and evening showers and thunderstorms. Ditto on Thursday. Our forecast area portions of southeast CA and southwest AZ will remain relatively dry and hot. Current forecasts look ok for now. No updates planned. .Previous Discussion...330 AM MST... Few showers/thunderstorms moving through central Arizona early this morning, associated with an upper level low who`s swirl can be seen in water vapor and infrared satellite images. Operational HRRR has not handled this feature and resultant precipitation well (just catching on the past few runs) but the HRRR-X is exhibiting much better performance. Based on current trends and HRRR-X forecast, expect shower activity to move north of Maricopa County by around 13 UTC/6 AM MST. For the rest of the day, mix of clouds in the morning should slow warming across central Arizona while southwest Arizona and southeast California enjoy fuller sunshine and quickly warming temperatures. Preponderance of high-res convective allowing models (CAMs) for today keep convection confined to the Rim area to our northwest and sky islands to our south. It does seem possible, especially from the NCAR Ensemble and SPC Storm-Scale of Opportunity Ensemble, that some outflow boundaries will make their way into the Phoenix area again this evening and perhaps touch of a few showers/storms. As usual, chance of outflows exceed chance of rain. This seems reasonable given a mixed boundary layer exceeding 700 mb but modest instability (mixed layer CAPE of around 300 J/kg) and warrants continued low but non- zero chances for precipitation. Further west...airmass remains too dry and stable to support any convection. Moisture really begins to thin out on Thursday as boundary layer mixing ratio values during the afternoon drop to about 8 g/kg or less across our entire CWA. Still a fleeting chance for precipitation as it is possible some lingering moisture could boost instability, but definitely on the downward trend. And as usually is the case for our climate this time of year, if the moisture decreases the temperatures take advantage. GFS/EC and GEFS point to 850 mb temperatures climbing to around 32C for Friday, which will yield high temperatures in the 110-115 range for the lower elevations. Given modest remnant moisture and perhaps nocturnal debris clouds, low temperatures at-or-above 90F seem quite likely Friday and Saturday mornings. Given these high end temperatures, we are issuing an Excessive Heat Watch for Friday focusing on the Phoenix area where the urban infrastructure will boost overnight lows. At this point it appears to be a marginal event, and confidence is moderate at this time for excessive heat conditions to come to fruition (hence issuance of a watch, which is not a guarantee by itself of course but highlight the enhanced risk). There is certainly plausible scenarios where excessive heat conditions persist into Saturday (or even develop early on Thursday). As the weekend progresses, the upper level (250 mb) flow pattern will be adjusting. The heat dome parked over the central CONUS today will be migrating southwest through Saturday (hence our heat event), but will become suppressed and weaken Sunday as a trough moves across the northern tier states. The southern edge of that trough appears as if it will develop into a shear axis that extends from near southern California into the Central Plains by the middle of next week. With a strong upper level anti-cyclone to our northwest, the cloud-bearing flow across Arizona will become much more easterly. Winds in the 700-500 mb layer will be 10-20 kt and propagation/Corfidi vectors will also be near 20 kt, all with an easterly flow. At the same time, appears the Sierra Madre will be lighting up with thunderstorms by next week, which is a great pumping mechanism to transport moisture into the Sonora Desert. This all points to the potential for a more active thunderstorm period beginning Tuesday and, should the heart of the 500 mb anti-cyclone stay in a preferred location to our north, continuing for well beyond our forecast period. && .AVIATION... South-Central Arizona Including KPHX, KIWA, and KSDL: Weather disturbance that led to overnight showers and isolated thunderstorms continued to weaken and move north of the area early this morning and currently expect morning precip to be of the shower variety. Expect scattered to broken mid/high level debris cloud decks into mid morning with most bases aoa 10k feet, with additional clearing by late morning/early afternoon. Another round of convection is possible this evening but due to the showers that already occurred and a stabilized boundary layer, they may be somewhat delayed and not especially vigorous if/when they occur. Will not mention thunder later on in the upcoming TAFs due to low confidence in formation/timing of any storms that do occur. Winds to favor the east this morning, turning to the west by mid afternoon. Should storms occur this evening, gusty outflow winds will likely impact the terminals, probably favoring a south to southeast direction. May see some blowing dust as well but visibilities at the terminals should stay above 3SM. Less convective activity is expected Thursday into Friday as monsoon moisture steadily thins out. Southeast California/Southwest Arizona including KIPL and KBLH: Little aviation concerns through with storm activity well off to the east into central Arizona. Expect mostly clear skies and southerly winds through the day today. Aviation Discussion not updated for amended TAFs. && .FIRE WEATHER... Friday through Tuesday...Temperatures will trend back into a well above normal range through the weekend as moisture levels thin and humidity values drop. Thunderstorm/wetting rain chances dwindle and become mostly limited to the higher terrain of eastern Arizona by Friday and Saturday. Consequently, afternoon humidity levels will fall below 15 percent over the lower deserts through Saturday, and then climb back into the 15-20 percent range Sunday into early next week as thunderstorms chances slowly increase from east to west. Higher RH values are expected across the higher terrain locations. Outside of any thunderstorms, winds will be typical with some afternoon gustiness. && .SPOTTER INFORMATION STATEMENT... Spotter activation may be required for this evening. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...Excessive Heat Watch from late Thursday night through Friday evening for AZZ023. CA...None. && $$ Visit us on Facebook...Twitter...and at weather.gov/phoenix DISCUSSION...Vasquez/Iniguez AVIATION...CB FIRE WEATHER...Deemer/Iniguez/CB
Area Forecast Discussion National Weather Service Flagstaff AZ 335 AM MST WED JUL 20 2016 .SYNOPSIS...Monsoon moisture will continue to keep showers and thunderstorms in the forecast through at least Thursday. Friday and into the weekend, a drier westerly flow will decrease shower coverage across northwestern Arizona with decent chances for thunderstorms across southern Navajo and Apache counties. && .DISCUSSION...Deep southerly flow continues to import plentiful moisture into the state this morning. A few light showers and an occasional lightning strike were noted at 3 am from around Williams into western Yavapai county and also southern Apache county. Later this morning through the afternoon, expecting another round of showers and thunderstorms, most numerous along the higher terrain though some storms will push northward into some lower terrain areas. Morning cloud cover could play a role in where storms develop first and how strong they become. A mid and upper level disturbance rotating northward across our region today could also act to enhance storm coverage. The main threats today will be locally heavy rainfall and flooding, with some hail and gusty winds with stronger storms as well. Similar conditions are expected Thursday, then a downward trend in moisture and storm activity is forecast starting Friday in the northern part of the state as the ridge axis sinks southward. However, due to the forecast position of the ridge axis, a tight moisture gradient is likely to set up across the area, with higher values of moisture in the southern portion of the forecast area. So we kept a chance of thunderstorms each day into early next week across the Mogollon Rim and White Mountains with generally slight chances elsewhere. There is still some uncertainty with where this moisture gradient sets up, so watch for updated forecasts as the pattern evolves. && .AVIATION...For the 12Z package...Isolated to scattered storms will continue this morning. Look for scattered to numerous SHRA/TSRA to redevelop between 17z-02z today. Brief MVFR/IFR conditions in the stronger storms with locally heavy rain, small hail, and gusty winds. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Scattered to numerous showers and thunderstorms can be expected today and again on Thursday. Storms will generally be moving slowly from south to north. Friday through Sunday...Drier air will start to filter in from the west, which will bring a decrease in thunderstorm activity, especially across the western portion of the state. Minimum RH values will drop back into the teens generally from Flagstaff north. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC...JJ AVIATION...MCS FIRE WEATHER...MCS For Northern Arizona weather information visit weather.gov/flagstaff
Area Forecast Discussion...Updated National Weather Service Phoenix AZ 330 AM MST WED JUL 20 2016 .UPDATE...Updated aviation and fire weather discussions. && .SYNOPSIS... The dry weather across southeast California and southwest Arizona will begin to spread eastward today, with chances for showers and thunderstorms gradually dwindling across central Arizona. By Friday, just low end chances will be confined to Arizona`s higher elevation areas. In response, temperatures will warm up with excessive heat conditions possible Friday. The weather pattern will undergo a transition during the weekend and it is looking possible that a more active pattern will become established next week. && .DISCUSSION... Few showers/thunderstorms moving through central Arizona early this morning, associated with an upper level low who`s swirl can be seen in water vapor and infrared satellite images. Operational HRRR has not handled this feature and resultant precipitation well (just catching on the past few runs) but the HRRR-X is exhibiting much better performance. Based on current trends and HRRR-X forecast, expect shower activity to move north of Maricopa County by around 13 UTC/6 AM MST. For the rest of the day, mix of clouds in the morning should slow warming across central Arizona while southwest Arizona and southeast California enjoy fuller sunshine and quickly warming temperatures. Preponderance of high-res convective allowing models (CAMs) for today keep convection confined to the Rim area to our northwest and sky islands to our south. It does seem possible, especially from the NCAR Ensemble and SPC Storm-Scale of Opportunity Ensemble, that some outflow boundaries will make their way into the Phoenix area again this evening and perhaps touch of a few showers/storms. As usual, chance of outflows exceed chance of rain. This seems reasonable given a mixed boundary layer exceeding 700 mb but modest instability (mixed layer CAPE of around 300 J/kg) and warrants continued low but non- zero chances for precipitation. Further west...airmass remains too dry and stable to support any convection. Moisture really begins to thin out on Thursday as boundary layer mixing ratio values during the afternoon drop to about 8 g/kg or less across our entire CWA. Still a fleeting chance for precipitation as it is possible some lingering moisture could boost instability, but definitely on the downward trend. And as usually is the case for our climate this time of year, if the moisture decreases the temperatures take advantage. GFS/EC and GEFS point to 850 mb temperatures climbing to around 32C for Friday, which will yield high temperatures in the 110-115 range for the lower elevations. Given modest remnant moisture and perhaps nocturnal debris clouds, low temperatures at-or-above 90F seem quite likely Friday and Saturday mornings. Given these high end temperatures, we are issuing an Excessive Heat Watch for Friday focusing on the Phoenix area where the urban infrastructure will boost overnight lows. At this point it appears to be a marginal event, and confidence is moderate at this time for excessive heat conditions to come to fruition (hence issuance of a watch, which is not a guarantee by itself of course but highlight the enhanced risk). There is certainly plausible scenarios where excessive heat conditions persist into Saturday (or even develop early on Thursday). As the weekend progresses, the upper level (250 mb) flow pattern will be adjusting. The heat dome parked over the central CONUS today will be migrating southwest through Saturday (hence our heat event), but will become suppressed and weaken Sunday as a trough moves across the northern tier states. The southern edge of that trough appears as if it will develop into a shear axis that extends from near southern California into the Central Plains by the middle of next week. With a strong upper level anti-cyclone to our northwest, the cloud-bearing flow across Arizona will become much more easterly. Winds in the 700-500 mb layer will be 10-20 kt and propagation/Corfidi vectors will also be near 20 kt, all with an easterly flow. At the same time, appears the Sierra Madre will be lighting up with thunderstorms by next week, which is a great pumping mechanism to transport moisture into the Sonora Desert. This all points to the potential for a more active thunderstorm period beginning Tuesday and, should the heart of the 500 mb anti-cyclone stay in a preferred location to our north, continuing for well beyond our forecast period. && .AVIATION... South-Central Arizona Including KPHX, KIWA, and KSDL: Weather disturbance that led to overnight showers and isolated thunderstorms continued to weaken and move north of the area early this morning and currently expect morning precip to be of the shower variety. Expect scattered to broken mid/high level debris cloud decks into mid morning with most bases aoa 10k feet, with additional clearing by late morning/early afternoon. Another round of convection is possible this evening but due to the showers that already occurred and a stabilized boundary layer, they may be somewhat delayed and not especially vigorous if/when they occur. Will not mention thunder later on in the upcoming TAFs due to low confidence in formation/timing of any storms that do occur. Winds to favor the east this morning, turning to the west by mid afternoon. Should storms occur this evening, gusty outflow winds will likely impact the terminals, probably favoring a south to southeast direction. May see some blowing dust as well but visibilities at the terminals should stay above 3SM. Less convective activity is expected Thursday into Friday as monsoon moisture steadily thins out. Southeast California/Southwest Arizona including KIPL and KBLH: Little aviation concerns through with storm activity well off to the east into central Arizona. Expect mostly clear skies and southerly winds through the day today. Aviation Discussion not updated for amended TAFs. && .FIRE WEATHER... Friday through Tuesday...Temperatures will trend back into a well above normal range through the weekend as moisture levels thin and humidity values drop. Thunderstorm/wetting rain chances dwindle and become mostly limited to the higher terrain of eastern Arizona by Friday and Saturday. Consequently, afternoon humidity levels will fall below 15 percent over the lower deserts through Saturday, and then climb back into the 15-20 percent range Sunday into early next week as thunderstorms chances slowly increase from east to west. Higher RH values are expected across the higher terrain locations. Outside of any thunderstorms, winds will be typical with some afternoon gustiness. && .SPOTTER INFORMATION STATEMENT... Spotter activation may be required for this evening. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...Excessive Heat Watch from late Thursday night through Friday evening for AZZ023. CA...None. && $$ Visit us on Facebook...Twitter...and at weather.gov/phoenix DISCUSSION...Iniguez AVIATION...CB FIRE WEATHER...Deemer/Iniguez/CB
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
1223 PM CDT WED JUL 20 2016 ...Update to aviation forecast discussion... .SHORT TERM...(Today and Tonight) Issued at 251 AM CDT WED JUL 20 2016 A warm night tonight with temperatures still near 80 in many locations. A little more southerly wind in past days likely keeping the boundary layer more more mixed than previous nights. Convection tonight is also farther north and west, leaving the forecast area under mostly clear skies at this hour. Temperatures rise a degree or two from yesterdays numbers, with highs in the middle 90s to near 100. Heat indicies running from 100-109F across the area as the excessive heat warning continues. A little more wind today but not likely to make it feel much cooler. Lows tonight fall into the middle 70s to near 80. .LONG TERM...(Thursday through Tuesday) Issued at 251 AM CDT WED JUL 20 2016 Only minor changes to previous forecast. Upper high still in place into the late week before weakening late Friday into the weekend. Southwest low level flow and general subsidence keep the hot conditions in place with little opportunity for precipitation. 850mb temps continue their rise into Thursday and remain fairly steady into Saturday with the main challenges being in the specifics of the air and wet bulb temps. Went on the warmer and drier side of guidance given model performance in recent similar environments. Heat index values still looking to reach 103 to 110 through Saturday. Upper wave passing over the northern states still looks to drag a cold front into the area Saturday night into Sunday for at least cooler temps and some chance for precipitation. Chances should linger into Tuesday as another wave takes a similar track to the north, with isentropic lift resulting. && .AVIATION...(For the 18Z TAFS through 18Z Thursday Afternoon) Issued at 1223 PM CDT WED JUL 20 2016 VFR conditions are expected through the period. LLWS criteria still looks best in central Kansas and have continued to leave this mention out of the TAFs. && .TOP Watches/Warnings/Advisories... Excessive Heat Warning until 7 PM CDT Saturday for KSZ008>012- 020>024-026-034>040-054>056-058-059. && $$ SHORT TERM...67 LONG TERM...65 AVIATION...Heller
Area Forecast Discussion National Weather Service Goodland KS 1119 AM MDT WED JUL 20 2016 .SHORT TERM...(Today and tonight) Issued at 300 AM MDT Wed Jul 20 2016 Short term concerns are hot temperatures over the next few days with heat index maximums near 105 and heat index minimums around 75 with the possibility of thunderstorms each day. The large high pressure area aloft over the central United States flattens somewhat through the end of the week and retrogrades back over the southwest as a couple of short wave troughs lift out of the southwest and track up the back side of the ridge and a larger upper trough tracks through the northwest U.S. along the Canadian border. The upper trough emerges east of the Rockies Friday night over southern Saskatchewan and eastern Montana. A persistent surface trough remains generally in place over the western portion of the forecast area through Friday with mainly south winds across the region ahead of the trough. As the upper ridge flattens over the central U.S. and the upper trough moves east of the northern Rockies by late Friday and over the northern plains by Friday night, a cold front is expected to begin moving into the central high plains region. Temperatures across the forecast area will remain hot ahead of this front with highs well in the 90s to lower 100s and lows in the 60s to middle 70s. Combined with dewpoints that remain mostly in the lower 60s across the northern and eastern extent of the forecast area, expect maximum heat index values near 105 with minimum heat index values in the middle 70s across the same area. The heat advisory remains in effect for those areas and looks to be on track, so will leave it as is. With short wave impulses moving east of the Rockies and across the plains each day with moisture convergence and increased instabilty in the vicinity of the surface trough over the western sections of the forecast area, expect isolated to scattered thunderstorms developing west of the forecast area each afternoon and evening to move eastward through the evening and overnight hours with storms dissipating as they move further east into the ridge. .LONG TERM...(Saturday through Tuesday) Issued at 233 AM MDT Wed Jul 20 2016 Ridge breaks down and slides westward as we head into Saturday and Sunday. A nearly stationary theta-e boundary associated with a cold front will be in place from southwest to northeast across the CWA on Saturday and will strengthen as we head into Sunday, allowing for slgt chc to chc PoPs across the area mainly during the mid afternoon through late evening. Surface low pressure will remain in place in the vicinity of this boundary due to lee side upper level divergent flow. CAPE values are expected to be up to 1600 J/Kg and shear will be very low thus severe potential will be limited to gusty winds and perhaps large hail in the presence of DCAPE values around 700 to 1200 J/Kg. Much cooler temperatures much closer to seasonal averages will prevail in the wake of this cold front. Troughing will take shape over the eastern US as we head into Monday. A cold front will push southward at this time and back into the CWA on Monday afternoon, giving us another chance of thunderstorms through the day and into the evening. There is some disagreement with the placement of the front however; both global models indicate the same general timing of the feature. The front will wash out as we head into Tuesday and a ridge will begin to build over the western states. && .AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon) Issued at 1119 AM MDT Wed Jul 20 2016 VFR conditions will continue through the TAF period at both KGLD and KMCK terminals. Thunderstorm activity may develop along a surface trough in eastern colorado and move into northwest Kansas and southwest Nebraska. Confidence was too low to include mention in either KGLD or KMCK TAF as coverage may remain very isolated. Winds should remain less than 12kt through the TAF period, though a LLJ developing tonight may lead to low level wind shear developing at both terminals. Confidence was higher in wind shear at KMCK, so I left mention out of KGLD for now. && .GLD Watches/Warnings/Advisories... KS...Heat Advisory until 7 PM CDT Friday for KSZ002>004-014>016-028- 029. CO...NONE. NE...Heat Advisory until 6 PM MDT /7 PM CDT/ Friday for NEZ079>081. && $$ SHORT TERM...LOCKHART LONG TERM...TL AVIATION...DR
Area Forecast Discussion National Weather Service Goodland KS 1119 AM MDT WED JUL 20 2016 .SHORT TERM...(Today and tonight) Issued at 300 AM MDT Wed Jul 20 2016 Short term concerns are hot temperatures over the next few days with heat index maximums near 105 and heat index minimums around 75 with the possibility of thunderstorms each day. The large high pressure area aloft over the central United States flattens somewhat through the end of the week and retrogrades back over the southwest as a couple of short wave troughs lift out of the southwest and track up the back side of the ridge and a larger upper trough tracks through the northwest U.S. along the Canadian border. The upper trough emerges east of the Rockies Friday night over southern Saskatchewan and eastern Montana. A persistent surface trough remains generally in place over the western portion of the forecast area through Friday with mainly south winds across the region ahead of the trough. As the upper ridge flattens over the central U.S. and the upper trough moves east of the northern Rockies by late Friday and over the northern plains by Friday night, a cold front is expected to begin moving into the central high plains region. Temperatures across the forecast area will remain hot ahead of this front with highs well in the 90s to lower 100s and lows in the 60s to middle 70s. Combined with dewpoints that remain mostly in the lower 60s across the northern and eastern extent of the forecast area, expect maximum heat index values near 105 with minimum heat index values in the middle 70s across the same area. The heat advisory remains in effect for those areas and looks to be on track, so will leave it as is. With short wave impulses moving east of the Rockies and across the plains each day with moisture convergence and increased instabilty in the vicinity of the surface trough over the western sections of the forecast area, expect isolated to scattered thunderstorms developing west of the forecast area each afternoon and evening to move eastward through the evening and overnight hours with storms dissipating as they move further east into the ridge. .LONG TERM...(Saturday through Tuesday) Issued at 233 AM MDT Wed Jul 20 2016 Ridge breaks down and slides westward as we head into Saturday and Sunday. A nearly stationary theta-e boundary associated with a cold front will be in place from southwest to northeast across the CWA on Saturday and will strengthen as we head into Sunday, allowing for slgt chc to chc PoPs across the area mainly during the mid afternoon through late evening. Surface low pressure will remain in place in the vicinity of this boundary due to lee side upper level divergent flow. CAPE values are expected to be up to 1600 J/Kg and shear will be very low thus severe potential will be limited to gusty winds and perhaps large hail in the presence of DCAPE values around 700 to 1200 J/Kg. Much cooler temperatures much closer to seasonal averages will prevail in the wake of this cold front. Troughing will take shape over the eastern US as we head into Monday. A cold front will push southward at this time and back into the CWA on Monday afternoon, giving us another chance of thunderstorms through the day and into the evening. There is some disagreement with the placement of the front however; both global models indicate the same general timing of the feature. The front will wash out as we head into Tuesday and a ridge will begin to build over the western states. && .AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon) Issued at 1119 AM MDT Wed Jul 20 2016 VFR conditions will continue through the TAF period at both KGLD and KMCK terminals. Thunderstorm activity may develop along a surface trough in eastern colorado and move into northwest Kansas and southwest Nebraska. Confidence was too low to include mention in either KGLD or KMCK TAF as coverage may remain very isolated. Winds should remain less than 12kt through the TAF period, though a LLJ developing tonight may lead to low level wind shear developing at both terminals. Confidence was higher in wind shear at KMCK, so I left mention out of KGLD for now. && .GLD Watches/Warnings/Advisories... KS...Heat Advisory until 7 PM CDT Friday for KSZ002>004-014>016-028- 029. CO...NONE. NE...Heat Advisory until 6 PM MDT /7 PM CDT/ Friday for NEZ079>081. && $$ SHORT TERM...LOCKHART LONG TERM...TL AVIATION...DR
Area Forecast Discussion National Weather Service Dodge City KS 1200 PM CDT WED JUL 20 2016 ...Updated Aviation... .SHORT TERM...(Today and tonight) Issued at 226 AM CDT Wed Jul 20 2016 For today, the heat continues with upper level warm ridging intact across the Central Plains. High temps will be dependent on 700 mb forecast temps that show not much change from yesterday. However more downslope surface winds will add a few degrees to highs today. Also with downslope and deep mixing, the dewpoints will mix out, so no heat headlines planned today. Highs will range from 101 west of Dodge to near 98 at Dodge City and around 101 from Medicine Lodge to Hays. South to southwest winds increase to 15 to 24 mph in the afternoon with a lee trough and clear skies. For tonight, south winds decrease to around 10 mph with clear skies. Overnight lows will range from around 70 far west near the Colorado border to the mid 70s across south central sections. .LONG TERM...(Thursday through Tuesday) Issued at 226 AM CDT Wed Jul 20 2016 For Thursday and Friday, the heat continues with 700 mb temps warming a few degrees. This will allow mix down temps to be a few degrees warmer and range from 100 to 104. However dewpoints below 65 are expected and likely not add to the heat index. Still these temps will be very close to heat advisory especially for south central sections where dewpoints will be the highest. Later shifts may need evaluate how much dewpoints mix out, and if heat advisories will be required for parts of the area. For the weekend into early next week. Shortwave troughs will traverse across the Plains with increasing chances for mainly late afternoon and evening scattered thunderstorms. These waves will allow the heat wave to break with highs back into the low to mid 90s from Sunday into Tuesday. && .AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon) Issued at 1200 PM CDT Wed Jul 20 2016 VFR/SKC through Thursday, with only a few cumulus each afternoon. SW winds gusting near 30 kts this afternoon, diminishing at sunset. Consensus of short term models again develops widespread low level wind shear starting around 06z, with 850 mb winds (LLJ) peaking around 45 kts. No changes Thursday; SKC and no convection with high pressure firmly in control. After 15z Thu, SW winds 15-25 kts at all airports. && .PRELIMINARY POINT TEMPS/POPS... DDC 98 74 101 74 / 0 0 0 10 GCK 101 72 101 71 / 0 0 0 10 EHA 100 72 101 71 / 0 0 0 10 LBL 100 73 103 72 / 0 0 0 10 HYS 101 75 102 74 / 0 0 0 10 P28 100 76 102 76 / 0 0 0 0 && .DDC Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Kruse LONG TERM...Kruse AVIATION...Turner
Area Forecast Discussion National Weather Service Dodge City KS 1200 PM CDT WED JUL 20 2016 ...Updated Aviation... .SHORT TERM...(Today and tonight) Issued at 226 AM CDT Wed Jul 20 2016 For today, the heat continues with upper level warm ridging intact across the Central Plains. High temps will be dependent on 700 mb forecast temps that show not much change from yesterday. However more downslope surface winds will add a few degrees to highs today. Also with downslope and deep mixing, the dewpoints will mix out, so no heat headlines planned today. Highs will range from 101 west of Dodge to near 98 at Dodge City and around 101 from Medicine Lodge to Hays. South to southwest winds increase to 15 to 24 mph in the afternoon with a lee trough and clear skies. For tonight, south winds decrease to around 10 mph with clear skies. Overnight lows will range from around 70 far west near the Colorado border to the mid 70s across south central sections. .LONG TERM...(Thursday through Tuesday) Issued at 226 AM CDT Wed Jul 20 2016 For Thursday and Friday, the heat continues with 700 mb temps warming a few degrees. This will allow mix down temps to be a few degrees warmer and range from 100 to 104. However dewpoints below 65 are expected and likely not add to the heat index. Still these temps will be very close to heat advisory especially for south central sections where dewpoints will be the highest. Later shifts may need evaluate how much dewpoints mix out, and if heat advisories will be required for parts of the area. For the weekend into early next week. Shortwave troughs will traverse across the Plains with increasing chances for mainly late afternoon and evening scattered thunderstorms. These waves will allow the heat wave to break with highs back into the low to mid 90s from Sunday into Tuesday. && .AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon) Issued at 1200 PM CDT Wed Jul 20 2016 VFR/SKC through Thursday, with only a few cumulus each afternoon. SW winds gusting near 30 kts this afternoon, diminishing at sunset. Consensus of short term models again develops widespread low level wind shear starting around 06z, with 850 mb winds (LLJ) peaking around 45 kts. No changes Thursday; SKC and no convection with high pressure firmly in control. After 15z Thu, SW winds 15-25 kts at all airports. && .PRELIMINARY POINT TEMPS/POPS... DDC 98 74 101 74 / 0 0 0 10 GCK 101 72 101 71 / 0 0 0 10 EHA 100 72 101 71 / 0 0 0 10 LBL 100 73 103 72 / 0 0 0 10 HYS 101 75 102 74 / 0 0 0 10 P28 100 76 102 76 / 0 0 0 0 && .DDC Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Kruse LONG TERM...Kruse AVIATION...Turner
Area Forecast Discussion National Weather Service Goodland KS 554 AM MDT WED JUL 20 2016 .SHORT TERM...(Today and tonight) Issued at 300 AM MDT Wed Jul 20 2016 Short term concerns are hot temperatures over the next few days with heat index maximums near 105 and heat index minimums around 75 with the possibility of thunderstorms each day. The large high pressure area aloft over the central United States flattens somewhat through the end of the week and retrogrades back over the southwest as a couple of short wave troughs lift out of the southwest and track up the back side of the ridge and a larger upper trough tracks through the northwest U.S. along the Canadian border. The upper trough emerges east of the Rockies Friday night over southern Saskatchewan and eastern Montana. A persistent surface trough remains generally in place over the western portion of the forecast area through Friday with mainly south winds across the region ahead of the trough. As the upper ridge flattens over the central U.S. and the upper trough moves east of the northern Rockies by late Friday and over the northern plains by Friday night, a cold front is expected to begin moving into the central high plains region. Temperatures across the forecast area will remain hot ahead of this front with highs well in the 90s to lower 100s and lows in the 60s to middle 70s. Combined with dewpoints that remain mostly in the lower 60s across the northern and eastern extent of the forecast area, expect maximum heat index values near 105 with minimum heat index values in the middle 70s across the same area. The heat advisory remains in effect for those areas and looks to be on track, so will leave it as is. With short wave impulses moving east of the Rockies and across the plains each day with moisture convergence and increased instabilty in the vicinity of the surface trough over the western sections of the forecast area, expect isolated to scattered thunderstorms developing west of the forecast area each afternoon and evening to move eastward through the evening and overnight hours with storms dissipating as they move further east into the ridge. .LONG TERM...(Saturday through Tuesday) Issued at 233 AM MDT Wed Jul 20 2016 Ridge breaks down and slides westward as we head into Saturday and Sunday. A nearly stationary theta-e boundary associated with a cold front will be in place from southwest to northeast across the CWA on Saturday and will strengthen as we head into Sunday, allowing for slgt chc to chc PoPs across the area mainly during the mid afternoon through late evening. Surface low pressure will remain in place in the vicinity of this boundary due to lee side upper level divergent flow. CAPE values are expected to be up to 1600 J/Kg and shear will be very low thus severe potential will be limited to gusty winds and perhaps large hail in the presence of DCAPE values around 700 to 1200 J/Kg. Much cooler temperatures much closer to seasonal averages will prevail in the wake of this cold front. Troughing will take shape over the eastern US as we head into Monday. A cold front will push southward at this time and back into the CWA on Monday afternoon, giving us another chance of thunderstorms through the day and into the evening. There is some disagreement with the placement of the front however; both global models indicate the same general timing of the feature. The front will wash out as we head into Tuesday and a ridge will begin to build over the western states. && .AVIATION...(For the 12Z TAFS through 12Z Thursday morning) Issued at 436 AM MDT Wed Jul 20 2016 VFR conditions will persist at GLD and MCK through the TAF period. South winds will become light through the day with LLWS possible after 06Z tonight. && .GLD Watches/Warnings/Advisories... KS...Heat Advisory from noon today to 7 PM CDT Friday for KSZ002>004- 014>016-028-029. CO...NONE. NE...Heat Advisory from 11 AM MDT /noon CDT/ this morning to 6 PM MDT /7 PM CDT/ Friday for NEZ079>081. && $$ SHORT TERM...LOCKHART LONG TERM...TL AVIATION...LOCKHART
Area Forecast Discussion National Weather Service Dodge City KS 654 AM CDT WED JUL 20 2016 ...Updated for aviation discussion... .SHORT TERM...(Today and tonight) Issued at 226 AM CDT Wed Jul 20 2016 For today, the heat continues with upper level warm ridging intact across the Central Plains. High temps will be dependent on 700 mb forecast temps that show not much change from yesterday. However more downslope surface winds will add a few degrees to highs today. Also with downslope and deep mixing, the dewpoints will mix out, so no heat headlines planned today. Highs will range from 101 west of Dodge to near 98 at Dodge City and around 101 from Medicine Lodge to Hays. South to southwest winds increase to 15 to 24 mph in the afternoon with a lee trough and clear skies. For tonight, south winds decrease to around 10 mph with clear skies. Overnight lows will range from around 70 far west near the Colorado border to the mid 70s across south central sections. .LONG TERM...(Thursday through Tuesday) Issued at 226 AM CDT Wed Jul 20 2016 For Thursday and Friday, the heat continues with 700 mb temps warming a few degrees. This will allow mix down temps to be a few degrees warmer and range from 100 to 104. However dewpoints below 65 are expected and likely not add to the heat index. Still these temps will be very close to heat advisory especially for south central sections where dewpoints will be the highest. Later shifts may need evaluate how much dewpoints mix out, and if heat advisories will be required for parts of the area. For the weekend into early next week. Shortwave troughs will traverse across the Plains with increasing chances for mainly late afternoon and evening scattered thunderstorms. These waves will allow the heat wave to break with highs back into the low to mid 90s from Sunday into Tuesday. && .AVIATION...(For the 12Z TAFS through 12Z Thursday morning) Issued at 653 AM CDT Wed Jul 20 2016 A surface trough will remain in the lee of the Rockies through the period, resulting in a continuation of south winds. The strongest winds will be during peak heating in the afternoon. VFR conditions will persist. && .PRELIMINARY POINT TEMPS/POPS... DDC 98 74 101 74 / 0 0 0 10 GCK 101 72 101 71 / 0 0 0 10 EHA 101 72 101 71 / 0 0 0 10 LBL 100 73 103 72 / 0 0 0 10 HYS 101 75 102 74 / 0 0 0 10 P28 100 76 102 76 / 0 0 0 0 && .DDC Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Kruse LONG TERM...Kruse AVIATION...Finch
Area Forecast Discussion National Weather Service Wichita KS 629 AM CDT WED JUL 20 2016 .SYNOPSIS... Issued at 303 AM CDT Wed Jul 20 2016 Impressive anticyclonic motion is evident on this mornings water vapor loop as upper-level ridging holds strong across the central CONUS. Cutoff energy continues to persist across the Pacific Northwest, with additional shortwave energy beginning to dig south across the Canadian Rocky Mountains. && .SHORT TERM...(Today through Friday night) Issued at 303 AM CDT Wed Jul 20 2016 No changes have been made to the inherited heat headlines once again. With many locations coming up short of the heat advisories criteria these past few days, have opted to leave the excessive heat warning as is for now. Over the next few days a possible expansion of the heat advisory and excessive heat warning will need to be monitored as the more substantial heat arrives. The heat really starts to crank up for the rest of the work week and into the weekend, with 1000-850mb partial thickness values easily supportive of widespread lower 100s across central and south central Kansas as 25-30C air advects northeast across the region each day. As we progress through the end of the work week, the dry, warm air aloft with gradually work its way further east. Therefore, expect dewpoints to mix out a bit more each day across the area. The worst heat indices still look to occur on Thursday when the feels like temperature may approach the 110 degree mark across portions of central Kansas. This does not seem unreasonable given the fact that temperatures are expected to approach the 104-105 degree mark. Unfortunately, little relief will be felt at night with overnight lows only dropping into the middle to upper 70s. There is a slight chance Friday night into Saturday for an isolated storm or two, but confidence is not high enough at this time to include any mentions higher than a slight chances across far central Kansas. .LONG TERM...(Saturday through Tuesday) Issued at 303 AM CDT Wed Jul 20 2016 As the upper-level ridge begins to break down towards the beginning of the weekend we could still see the 100 degree temperatures continue through the day on Saturday. However, the big question will be at that point how low dewpoints will get with ample mixing spanning numerous prior days. Given the uncertainty have opted to hold off on extending heat headlines into Saturday for now. With the above mentioned upper-level ridge breaking down as a trough begins to dig across the Northern Plains, a frontal boundary will begin to slowly drop south across the region. This will bring periodic chances for storms towards the end of the weekend and into the first half of the work week. Accompanying these chances for precipitation, temperatures will "cool down" to near normal for this time of year. && .AVIATION...(For the 12Z TAFS through 12Z Thursday morning) Issued at 629 AM CDT Wed Jul 20 2016 VFR conditions are expected for the next 24 hours. Could see some fair weather cumulus near the KCNU, KSLN and KICT Tafs. Ketcham && .PRELIMINARY POINT TEMPS/POPS... Wichita-KICT 100 77 101 77 / 0 0 0 10 Hutchinson 100 77 102 77 / 0 0 0 10 Newton 99 77 101 77 / 0 0 0 10 ElDorado 97 77 99 77 / 0 0 0 0 Winfield-KWLD 98 77 100 77 / 0 0 0 0 Russell 102 76 104 75 / 0 0 0 10 Great Bend 101 75 104 75 / 0 0 0 10 Salina 101 78 105 78 / 0 0 0 10 McPherson 100 77 103 76 / 0 0 0 10 Coffeyville 96 75 98 75 / 10 0 0 0 Chanute 95 76 97 76 / 10 0 0 0 Iola 95 76 97 76 / 10 0 0 0 Parsons-KPPF 95 76 97 76 / 10 0 0 0 && .ICT Watches/Warnings/Advisories... Heat Advisory until 8 PM CDT Friday for KSZ051-068-069-083- 092>096-098>100. Heat Advisory from noon today to 8 PM CDT Friday for KSZ033-048- 050-067-082-091. Excessive Heat Warning until 8 PM CDT Friday for KSZ049-052-053- 070>072. && $$ SYNOPSIS...JMR SHORT TERM...JMR LONG TERM...JMR AVIATION...BDK
Area Forecast Discussion National Weather Service Goodland KS 350 AM MDT WED JUL 20 2016 .SHORT TERM...(Today and tonight) Issued at 300 AM MDT Wed Jul 20 2016 Short term concerns are hot temperatures over the next few days with heat index maximums near 105 and heat index minimums around 75 with the possibility of thunderstorms each day. The large high pressure area aloft over the central United States flattens somewhat through the end of the week and retrogrades back over the southwest as a couple of short wave troughs lift out of the southwest and track up the back side of the ridge and a larger upper trough tracks through the northwest U.S. along the Canadian border. The upper trough emerges east of the Rockies Friday night over southern Saskatchewan and eastern Montana. A persistent surface trough remains generally in place over the western portion of the forecast area through Friday with mainly south winds across the region ahead of the trough. As the upper ridge flattens over the central U.S. and the upper trough moves east of the northern Rockies by late Friday and over the northern plains by Friday night, a cold front is expected to begin moving into the central high plains region. Temperatures across the forecast area will remain hot ahead of this front with highs well in the 90s to lower 100s and lows in the 60s to middle 70s. Combined with dewpoints that remain mostly in the lower 60s across the northern and eastern extent of the forecast area, expect maximum heat index values near 105 with minimum heat index values in the middle 70s across the same area. The heat advisory remains in effect for those areas and looks to be on track, so will leave it as is. With short wave impulses moving east of the Rockies and across the plains each day with moisture convergence and increased instabilty in the vicinity of the surface trough over the western sections of the forecast area, expect isolated to scattered thunderstorms developing west of the forecast area each afternoon and evening to move eastward through the evening and overnight hours with storms dissipating as they move further east into the ridge. .LONG TERM...(Saturday through Tuesday) Issued at 233 AM MDT Wed Jul 20 2016 Ridge breaks down and slides westward as we head into Saturday and Sunday. A nearly stationary theta-e boundary associated with a cold front will be in place from southwest to northeast across the CWA on Saturday and will strengthen as we head into Sunday, allowing for slgt chc to chc PoPs across the area mainly during the mid afternoon through late evening. Surface low pressure will remain in place in the vicinity of this boundary due to lee side upper level divergent flow. CAPE values are expected to be up to 1600 J/Kg and shear will be very low thus severe potential will be limited to gusty winds and perhaps large hail in the presence of DCAPE values around 700 to 1200 J/Kg. Much cooler temperatures much closer to seasonal averages will prevail in the wake of this cold front. Troughing will take shape over the eastern US as we head into Monday. A cold front will push southward at this time and back into the CWA on Monday afternoon, giving us another chance of thunderstorms through the day and into the evening. There is some disagreement with the placement of the front however; both global models indicate the same general timing of the feature. The front will wash out as we head into Tuesday and a ridge will begin to build over the western states. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) Issued at 1030 PM MDT Tue Jul 19 2016 For KGLD and KMCK, vfr conditions expected through the period. Only a few mid and high clouds expected through the period. Winds begin the period from the south to southeast occasionally gusting near 20kts. This continues overnight with a slight veering to the southwest around 10kts or so after 14z. Both terminals will see wind shear in the 07z-12z timeframe. && .GLD Watches/Warnings/Advisories... KS...Heat Advisory from noon today to 7 PM CDT Friday for KSZ002>004- 014>016-028-029. CO...NONE. NE...Heat Advisory from 11 AM MDT /noon CDT/ this morning to 6 PM MDT /7 PM CDT/ Friday for NEZ079>081. && $$ SHORT TERM...LOCKHART LONG TERM...TL AVIATION...99
Area Forecast Discussion National Weather Service Goodland KS 237 AM MDT WED JUL 20 2016 .SHORT TERM...(This afternoon through Wednesday) Issued at 147 PM MDT Tue Jul 19 2016 Early afternoon WV imagery and RAP upper level analysis show large scale ridge centered over the plains dominating the pattern across the US. Moist monsoonal plume is wrapping around the western extent of ridge into the Rockies. At the surface; low pressure is in place across eastern Colorado with a trough axis extending from northeast Colorado and across northern Kansas. Southwest flow is in place across much of our cwa. This afternoon-Wednesday: Mean storm track remains well west of our CWA with focus mainly in the central Rockies. A few weak shortwaves may try rotating towards the northwest part of our CWA. West and northwest parts of our CWA (near surface trough) also have better chance to see any thunderstorm activity due to weaker CAP and better instability. Further south and east in our CWA guidance shows a stronger CAP and eventually a significant decrease in CAPE as profiles warm and dry out during the afternoon periods. Strongest precip signal in guidance matches with these trends (northwest). A slightly stronger shortwave and shift in trough axis Wednesday (as indicated by some models) may support a few thunderstorms moving a little further east-southeast Wednesday afternoon (far northwest Kansas). Regarding temperatures/heat indices: Air mass aloft is only expected to become warmer and consensus shows highs 2-4F warmer than today. A major question on heat indices is Tds (which may mix lower in our west). As Tds decrease below 60 heat indices actually decrease from ambient temperature. Td recovery during the nighttime periods we will see overnight heat indices in the 68-76 range (minimum) which is quite mild for our CWA. There may be a few counties along western periphery of current heat advisory that remain below "exact" advisory criteria, but it is close enough and considering the very warm nighttime heat indices and several days in a row of the hot temperatures the decision was made to upgrade watch to heat advisory. Consecutive day requirement is not expected to be met for issuance of heat warning at this time, so advisory was favored. .LONG TERM...(Saturday through Tuesday) Issued at 233 AM MDT Wed Jul 20 2016 Ridge breaks down and slides westward as we head into Saturday and Sunday. A nearly stationary theta-e boundary associated with a cold front will be in place from southwest to northeast across the CWA on Saturday and will strengthen as we head into Sunday, allowing for slgt chc to chc PoPs across the area mainly during the mid afternoon through late evening. Surface low pressure will remain in place in the vicinity of this boundary due to lee side upper level divergent flow. CAPE values are expected to be up to 1600 J/Kg and shear will be very low thus severe potential will be limited to gusty winds and perhaps large hail in the presence of DCAPE values around 700 to 1200 J/Kg. Much cooler temperatures much closer to seasonal averages will prevail in the wake of this cold front. Troughing will take shape over the eastern US as we head into Monday. A cold front will push southward at this time and back into the CWA on Monday afternoon, giving us another chance of thunderstorms through the day and into the evening. There is some disagreement with the placement of the front however; both global models indicate the same general timing of the feature. The front will wash out as we head into Tuesday and a ridge will begin to build over the western states. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) Issued at 1030 PM MDT Tue Jul 19 2016 For KGLD and KMCK, vfr conditions expected through the period. Only a few mid and high clouds expected through the period. Winds begin the period from the south to southeast occasionally gusting near 20kts. This continues overnight with a slight veering to the southwest around 10kts or so after 14z. Both terminals will see wind shear in the 07z-12z timeframe. && .GLD Watches/Warnings/Advisories... KS...Heat Advisory from noon today to 7 PM CDT Friday for KSZ002>004- 014>016-028-029. CO...NONE. NE...Heat Advisory from 11 AM MDT /noon CDT/ this morning to 6 PM MDT /7 PM CDT/ Friday for NEZ079>081. && $$ SHORT TERM...DR LONG TERM...TL AVIATION...99