599
FXUS63 KDMX 281905
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
205 PM CDT SAT MAR 28 2026
KEY MESSAGES
- DO NOT BURN TODAY! CRITICAL FIRE WEATHER CONDITIONS/RED FLAG
WARNING UNTIL MID-EVENING.
- WARMER SUNDAY INTO MONDAY WITH NEAR RECORD HIGHS POSSIBLE IN A
FEW PLACES MONDAY. ELEVATED FIRE WEATHER CONDITIONS POSSIBLE
IN PORTIONS OF IOWA MONDAY.
- STORM POTENTIAL MONDAY NIGHT OVER NORTH CENTRAL/NORTHEASTERN IOWA
WITH LARGE HAIL THE MAIN THREAT.
- TURNING COOLER TUESDAY WITH BREEZY WINDS, THEN ON AND OFF
PRECIPITATION CHANCES REMAINDER OF THE WEEK.
SHORT TERM /THROUGH MONDAY/
ISSUED AT 205 PM CDT SAT MAR 28 2026
BREEZY WINDS FROM THE SOUTH OR SOUTH-SOUTHWEST PREVAIL EARLY
THIS AFTERNOON GUSTING BETWEEN 20 AND 35 MPH AS SURFACE HIGH
PRESSURE DEPARTS IOWA INTO THE OHIO VALLEY AND LOW PRESSURE
DEVELOPS OVER THE CENTRAL ROCKIES TIGHTENING THE PRESSURE
GRADIENT OVER THE STATE. THESE WINDS HAVE AIDED ENTRAINING DRIER
AIR TO THE SURFACE WITH SINGLE DIGIT DEWPOINTS IN NORTHWEST
IOWA. WITH RELIABLE RELATIVE HUMIDITY VALUES IN THE TEENS AND
THESE WINDS, THE CRITICAL FIRE WEATHER CONDITIONS ARE PRESENT.
THE PATCHES OF CLOUDS FROM EARLIER TODAY HAVE LARGELY THINNED
OUT OVER SOUTHERN IOWA AND MOVED OUT OF NORTH CENTRAL IOWA
LEAVING GOOD VIEWING OF ANY HOTSPOTS FROM FIRE. SHORTWAVE IR
IMAGERY SHOWS JUST A HANDFUL OF FIRES - SIGNIFICANTLY LESS THAN
LAST WEEKEND. WINDS WILL DIMINISH THIS EVENING AS THE NOCTURNAL
BOUNDARY LAYER DEVELOPS AND RELATIVE HUMIDITY VALUES BEGIN THEIR
RECOVERY TO ALLOW THE RED FLAG WARNING TO END MID-EVENING. PART
OF THIS RECOVERY WILL BE DRIVEN BY LOW LEVEL WARM AIR
ADVECTION, WHICH WILL DRAW HIGHER DEWPOINTS INTO IOWA AS SURFACE
WINDS REMAIN AROUND 10 TO 15 MPH THROUGH DAYBREAK SUNDAY. WHILE
SUNDAY WILL BE WARMER WITH HIGHS WELL INTO THE 70S, WINDS NOT
AS STRONG AND HIGHER DEWPOINTS AND RESULTANT MINIMUM RELATIVE
HUMIDITY VALUES IN THE 30 PERCENT RANGE WILL MITIGATE A CRITICAL
FIRE WEATHER DAY WITH GRASSLAND FIRE DANGER INDEX (GFDI) MAINLY
PEAKING IN THE HIGH CATEGORY (LEVEL 3 OUT OF A MAX OF 5).
THE LOW PRESSURE OVER THE ROCKIES WILL SLOWLY DRIFT EASTWARD ALONG
AN EAST-WEST BOUNDARY, WHICH WILL BE NORTH OF THE STATE ON MONDAY.
WITH IOWA IN THE WARM SECTOR AND 900MB TEMPERATURE CHANGE FROM
SUNDAY TO MONDAY OF ALMOST 10 DEGREES CELSIUS, WILL SEE HIGHS SHOOT
WELL INTO THE 70S AND THE 80S. FOR A FEW PLACES IN IOWA, THIS WILL
PUSH HIGHS TO NEAR RECORD LEVELS (SEE CLIMATE SECTION BELOW). WHILE
DEWPOINTS WILL BE HIGHER, THESE HIGHER TEMPERATURES AND SLIGHTLY
MORE BREEZY WINDS DO KICK THE GFDI INTO THE VERY HIGH CATEGORY IN
SOUTHERN AND PARTS OF WESTERN IOWA. SO, WHILE NOT CRITICAL, IT COULD
BE AN ELEVATED FIRE WEATHER DAY.
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/
ISSUED AT 205 PM CDT SAT MAR 28 2026
AS THE SUN SETS MONDAY EVENING, WILL BE MONITORING FOR POSSIBLE
STORM DEVELOP IN THE VICINITY OF THE EAST-WEST BOUNDARY AS THETA-E
ADVECTION PUSHES INTO IT OVERNIGHT. THE LOW LEVEL JET WILL BE
INCREASING TO BETWEEN 35 TO 45 KNOTS WITH AN ENVIRONMENT
CHARACTERIZED BY MUCAPES OVER 1000 J/KG, EFFECTIVE SHEAR OF 30ISH
KNOTS, AND 3-6KM LAPSE RATES OF 8C/KM. MODELS ARE QUITE DIVERSE IN
THEIR HANDLING AND THERE IS LIMITED CONVECTIVE ALLOWING MODEL (CAM)
GUIDANCE AT THIS RANGE (E.G. RRFS, MPAS), BUT IT SEEMS SOMEWHERE
OVER NORTH CENTRAL INTO NORTHEASTERN IOWA MAY BE THE STORM GENESIS
REGION. FORECAST SOUNDINGS POINT TO ELEVATED STORMS, WHICH WOULD
POSE A RISK OF LARGE HAIL. THIS SEEMS TO BE THE MAIN RISK DESPITE
FAVORABLE DOWNDRAFT CAPE VALUES OVER 1000 J/KG DUE TO EXPECTED HIGH
CLOUD BASES AND MORE STABLE LOW LEVELS WITH LAPSE RATES AROUND 5
C/KM.
AS A NORTHERN STREAM SHORTWAVE TROUGH PUSHES DOWN FROM THE CANADIAN
PRAIRIES INTO THE FAR NORTHERN STATES, THIS WILL GIVE THE SURFACE
LOW A NUDGE EASTWARD AND DRAG THE BOUNDARY INTO THE STATE AS A COLD
FRONT ON TUESDAY. THERE MAY BE A BRIEF WINDOW IN OUR FAR
SOUTHEASTERN FORECAST AREA (E.G. OTTUMWA, CENTERVILLE) FOR A FEW
STORMS ALONG THIS FRONT, BUT THE HIGHER RISK WILL LIKELY BE
SOUTHEAST OF IOWA. WINDS WILL BE BREEZY BEHIND THE FRONT WITH HIGHS
LOWER BY NEARLY 30 DEGREES IN NORTHWEST IOWA TO 5 TO 10 DEGREES
LOWER IN SOUTHEAST IOWA. WHILE THIS FRONT IS MOVING THROUGH OUR
REGION, THE NEXT, WEAK SHORTWAVE TROUGH WILL BE COMING ONSHORE OVER
CALIFORNIA AND MOVING QUICKLY EASTWARD REACHING OUR REGION BY
WEDNESDAY NIGHT INTO THURSDAY MORNING. WHILE GULF MOISTURE WILL BE
LIFTED AHEAD OF THIS WAVE TOWARD IOWA, IT LOOKS TO BE LIMITED AND
MORE SHUNTED TO THE EAST. THE LIMITED MOISTURE WILL STILL BE
SUFFICIENT FOR PRECIPITATION OVER AT LEAST SOUTHERN IOWA SOMETIME
LATER WEDNESDAY OR THURSDAY WITH THE BROAD TIME WINDOW DUE TO
UNCERTAINTY. WHILE MUCH OF THIS WILL BE IN THE FORM OF LIQUID,
CANNOT FULLY RULE OUT WET SNOWFLAKES MIXED IN ON THE NORTHERN EDGE
OF THE EVENTUAL PRECIPITATION SHIELD. A MORE AMPLIFIED TROUGH PUSHES
TOWARDS THE REGION LATE NEXT WEEK INTO NEXT WEEKEND, WHICH SHOULD
BRING BACK RAIN CHANCES AND PERHAPS INSTABILITY FOR STORM POTENTIAL
FRIDAY AND/OR SATURDAY.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 1224 PM CDT SAT MAR 28 2026
THERE IS HIGH CONFIDENCE IN VFR CONDITIONS THROUGH THE PERIOD AT
THE TERMINALS. THERE ARE SOME CLOUDS ACROSS CENTRAL IOWA EARLY
THIS AFTERNOON, BUT ALL THEIR BASES WILL BE ABOVE FL090 OR SO.
GUSTY WINDS FROM THE SOUTH WILL DIMINISH SOME INTO TONIGHT, BUT
WILL STILL BE BREEZY AVERAGING AROUND 10 KNOTS. WITH AN
INVERSION DEVELOPING AND WINDS AT THE TOP OF THE LAYER STRONGER,
THERE IS A CHANCE FOR LOW LEVEL WIND SHEAR (LLWS). HOWEVER, THE
MAGNITUDE IS JUST UNDER 30 KNOTS SO HAVE OMITTED THIS MARGINAL
LLWS FOR NOW. WINDS FROM THE SOUTHWEST WILL INCREASE THROUGH
SUNDAY MORNING TO BE BETWEEN 11 AND 16 KNOTS BY THE END OF THE
PERIOD.
CLIMATE
ISSUED AT 205 PM CDT SAT MAR 28 2026
...FORECAST AND RECORD HIGH TEMPERATURES FOR SELECT CENTRAL IOWA
CITIES...
=============================================
| MONDAY | PERIOD
| FORECAST RECORD/ | OF
CITY | HIGH YEAR | RECORD
=============================================
DES MOINES 83 83/1968 1878-
MASON CITY 79 78/1967 1903-
OTTUMWA 84 83/1967 1923-
WATERLOO 79 84/1967 1895-
=============================================
DMX WATCHES/WARNINGS/ADVISORIES
RED FLAG WARNING UNTIL 9 PM CDT THIS EVENING FOR IAZ004>007-
015>017-023>028-033>039-044>050-057>062-070>075-081>086-
092>097.
SHORT TERM...ANSORGE
LONG TERM...ANSORGE
AVIATION...ANSORGE
CLIMATE...ANSORGE
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