519
FXUS65 KCYS 182320
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
520 PM MDT SAT JUL 18 2026
KEY MESSAGES
- HOT, DRY, AND BREEZY CONDITIONS CONTINUE THROUGH SUNDAY NIGHT BEFORE
A MUCH AWAITED COLD FRONT ARRIVES FOR THE START OF THE WEEK.
- DAILY INCREASING CHANCES FOR AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS ARE EXPECTED FOR TUESDAY ONWARD, WITH
BENEFICIAL RAINS MOST LIKELY ON TUESDAY, WEDNESDAY, THURSDAY
AND SATURDAY. THE SUMMER HEAT WILL BE MODERATED AND TEMPERED
BY EXTENSIVE CLOUD COVER AND PRECIPITATION COVERAGE MUCH OF
THE EXTENDED PERIOD WITH WARMER TEMPERATURES FOR SATURDAY.
SHORT TERM /THROUGH MONDAY NIGHT/
ISSUED AT 1240 PM MDT SAT JUL 18 2026
THE UPPER LEVEL RIDGE IS BACK OVER US AND IT SHIFTED BACK WESTWARD.
THE MAIN AREA OF HIGH CENTRAL PRESSURE KIND OF DRIFTS BETWEEN
CENTRAL COLORADO AND NEW MEXICO/WEST TEXAS AREA. THIS RIDGE WILL
KEEP THE AFTERNOON HIGH TEMPERATURES IN THE MID TO UPPER 90'S EAST
OF I-25. FOR THE HIGHER ELEVATIONS TOWNS WEST OF I-25, THE
TEMPERATURES ARE STILL GOING TO FAIRLY WARM IN THE MID TO UPPER
80'S. NO CHANGES WERE MADE TO THE HEAT ADVISORY AS THE SOUTHERN
COUNTIES AREN'T EXPECTED TO BE NEAR OR EXCEED 100 AS SOUTHERLY FLOW
AND THE HIGHER MOISTURE CONTENT ARE EXPECTED TO TEMPER THE HEAT A
LITTLE BIT, HOWEVER THEY ARE BORDERLINE CRITERIA FOR A HEAT ADVISORY
SINCE IT WILL TAKE UNTIL ABOUT 2AM TO DROP BELOW 70 DEGREES
OVERNIGHT. ULTIMATELY AFTER DISCUSSION WITH OUR NEIGHBORING OFFICES
THE EXPANSION OF THE HEAT ADVISORY WILL BE PUNTING TO THE NIGHT
SHIFT TO DECIDE WITH THE BORDERLINE CONDITIONS. AFTERNOON SHOWERS
ARE IN STORE FOR MAINLY CARBON COUNTY AND THE MOUNTAIN TOPS TODAY
AND MONDAY. THERE ARE A COUPLE VORT-MAXES TO INCREASE THE SYNOPTIC
LIFT TO DEVELOP SOME SHOWERS. THE FORCING AND PROJECTED AVAILABLE
CAPE LOOK PRETTY MEAGER OUTSIDE THE FEW VORT-MAXES. HI-RES GUIDANCE
ONLY PUTS A COUPLE HUNDRED JOULES OVER THE OUTER EDGES OF OUR CWA
WITH THE SOUNDINGS DEPICTING A PRETTY STOUT DRY LAYER NEAR THE
SURFACE. OUTSIDE OF YOUR REGULAR DIURNAL SHOWERS NOT MUCH IS
EXPECTED TO EVOLVE IN THE AFTERNOON. MONDAY, LOOK TO BE RATHER
SIMILAR TO SUNDAY IN THE ASPECT OF HOT AND DRY CONDITIONS FOR THE
VAST MAJORITY EAST OF I-25 AND AFTERNOON SHOWERS FOR THE MOUNTAINOUS
AREAS WITH LITTLE RAIN EXPECTED TO REACH THE SURFACE. FORCING DOES
SHIFT A LITTLE MORE EAST WITH A TOUCH HIGHER CAPE VALUES FOR MONDAY
AFTERNOON TO EXTENDED THE POSSIBLE SHOWER/THUNDERSTORM CHANCES TO
CHEYENNE HOWEVER THE THUNDERSTORMS HAVE TO MAKE IT DOWN THE
MOUNTAINS FIRST AND OVERCOME THE EXTENSIVE DRY LAYER. SHOWERS/
THUNDERSTORM DEVELOPMENT SHOULD BE DONE BY THE EVENING WITH FULL
DISSIPATION OF ANY STORMS/SHOWERS BY MIDNIGHT.
LONG TERM /TUESDAY THROUGH SATURDAY/
ISSUED AT 1240 PM MDT SAT JUL 18 2026
TUESDAY...A DECENT PATTERN CHANGE ENSUES WITH THE RIDGE FLATTENING
SOMEWHAT, HELPING MONSOONAL MOISTURE TO SPREAD ACROSS OUR WESTERN
COUNTIES, SPAWNING SCATTERED TO NUMEROUS SHOWERS AND SCATTERED
THUNDERSTORMS IN THE AFTERNOON, PRIMARILY FOCUSED WEST OF I-25.
WEDNESDAY...BENEFICIAL RAINS WILL BECOME MORE IN AREAL COVERAGE WITH
S DECENT INCREASE IN LOW LEVEL DEWPOINTS AND MID LEVEL MONSOONAL
MOISTURE AND UPSLOPE MECHANICAL SOUTHEAST WINDS ADVECTING LOW LEVEL
MOISTURE INTO OUR COUNTIES. WILL SEE SCATTERED TO NUMEROUS AFTERNOON
AND EVENING SHOWER AND THUNDERSTORM COVERAGE, MOST PREVALENT ALONG
THE I-25 CORRIDOR WHERE LIFT AND OROGRAPHIC LIFT WILL BE MAXIMIZED
CORRESPONDING TO THE DEEPEST MOISTURE SUPPLY.
THURSDAY...SOMEWHAT DRIER AIR INFILTRATES OUR COUNTIES AS THE FLOW
ALOFT TURNS WESTERLY WITH SOME DRY AIR INTRUSION AT LOW AND MID
LEVELS, AS THE SURFACE TROUGH OR DRYLINE MOVES TO CENTRAL NEBRASKA.
FRIDAY...RIDGING ALOFT BECOMES MORE PRONOUNCED, THOUGH WITH ENOUGH
MID LEVEL MOISTURE, WILL SEE TYPICAL ISOLATED TO SCATTERED SHOWERS
AND SOME THUNDERSTORMS IN THE AFTERNOON AND EVENING, MAINLY WEST OF
I-25 AND CONCENTRATED OVER THE MOUNTAINS.
SATURDAY...THE RIDGE BECOMES LESS PRONOUNCED ALONG WITH AN INCREASE
IN LOW AND MID LEVEL MOISTURE, AND WITH MORE MONSOONAL MOISTURE
PRESENT, AFTERNOON AND EVENING SHOWER AND THUNDERSTORM COVERAGE WILL
LIKELY NEED TO BE INCREASED AS WE APPROACH DAY SEVEN, PROVIDING MORE
BENEFICIAL RAINS.
AVIATION /00Z TAFS THROUGH 00Z MONDAY/
ISSUED AT 520 PM MDT SAT JUL 18 2026
VFR CONDITIONS WILL PREVAIL ACROSS ALL TERMINALS FOR THE DURATION OF
THIS TAF PERIOD. WINDS WILL DIMINISH THROUGH THE OVERNIGHT HOURS TO
GENERALLY LESS THAN 10 KNOTS, AND REMAIN SO INTO SUNDAY AFTERNOON
ACROSS THE SOUTHEAST WYOMING SITES. WHILE, THE NEBRASKA TERMINALS
WILL SEE AN UPTICK IN WINDS BY 17Z SUNDAY WITH GUSTS TO AROUND 20
KNOTS.
CYS WATCHES/WARNINGS/ADVISORIES
WY...HEAT ADVISORY FROM NOON SUNDAY TO 6 PM MDT MONDAY FOR WYZ101-
102-108.
NE...HEAT ADVISORY UNTIL 6 PM MDT MONDAY FOR NEZ002-095.
HEAT ADVISORY FROM NOON SUNDAY TO 6 PM MDT MONDAY FOR NEZ003-
019>021-096.
SHORT TERM...MM
LONG TERM...RUBIN
AVIATION...RZ
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