606
FXUS63 KBIS 191812
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
112 PM CDT SUN MAY 19 2013
UPDATE
ISSUED AT 112 PM CDT SUN MAY 19 2013
NO SIGNIFICANT CHANGES REQUIRED WITH THIS FORECAST UPDATE AS THE
FORECAST FOR THE REMAINDER OF THE AFTERNOON IS WELL ON TRACK AS
THE BAND OF MODERATE TO HEAVY RAIN ASSOCIATED WITH THE LOW LEVEL
DEFORMATION ZONE CONTINUES TO SLOWLY RETROGRADE WEST. STARTING TO
GET A FEW BREAKS IN THE CLOUDS ACROSS THE SOUTHERN JAMES RIVER
VALLEY...AND WILL BE MONITORING THIS AREA FOR DESTABILIZATION FOR
POTENTIAL AFTERNOON THUNDERSTORM DEVELOPMENT. BEING SO CLOSE TO
THE SURFACE LOW...DEEP LAYER SHEAR IS MARGINAL FOR THIS PART OF
THE CWA...HOWEVER...IT WOULD BE FAVORED FOR A POSSIBLE WEAK SPIN-
UP TORNADO/LAND SPOUT WITH THE LOW LEVEL VORTICITY SHOULD SUFFICIENT
NEAR SURFACE DESTABILIZATION OCCUR. THE FAR WEST AND NORTH CENTRAL
MAY APPROACH WIND ADVISORY CRITERIA LATE THIS AFTERNOON AND
THROUGH THE NIGHT. DID INCREASE WINDS...HOWEVER...WILL MONITOR
OBSERVED TRENDS THROUGH THE AFTERNOON FOR NOW.
IN REGARDS TO HYDRO...DID ISSUE A FLOOD WARNING FOR THE PIPESTEM
CREEK NEAR PINGREE.
UPDATE ISSUED AT 950 AM CDT SUN MAY 19 2013
BASED UPON THE 13 UTC RAP/HRRR AND RADAR TRENDS...DID LOWER POPS
ACROSS THE JAMES RIVER VALLEY THROUGH THE REMAINDER OF THE DAY AS
THE MAIN BAND OF STRATIFORM RAINFALL ASSOCIATED WITH THE LOW
LEVEL DEFORMATION ZONE SLOWLY RETROGRADES WEST THROUGH THE DAY.
THE MAIN QUESTION FOR THE JAMES RIVER VALLEY IS HOW MUCH
DESTABILIZATION WILL OCCUR WITH ANY BREAKS IN CLOUD COVER THIS
AFTERNOON. SHOULD THIS OCCUR...ISOLATED TO SCATTERED THUNDERSTORMS
ARE POSSIBLE...A FEW OF WHICH COULD PRODUCE SMALL HAIL. CANNOT
RULE OUT A SEVERE STORM ACROSS THE VERY FAR SOUTHEAST PORTIONS OF
THE CWA. HOWEVER WITH MARGINAL SHEAR AND UNCERTAINTY IN
DESTABILIZATION...WILL LEAVE THE SEVERE MENTION OUT FOR NOW.
SEE THE HYDROLOGY DISCUSSION BELOW REGARDING HEAVY RAIN IMPACTS TO
AREA RIVERS AND STREAMS.
.UPDATE ISSUED AT 700 AM CDT SUN MAY 19 2013
UPDATE TO REFINE POPS TODAY...AS RAIN HAS TEMPORARILY ENDED ACROSS
THE SOUTHEAST. ADDITIONAL REDEVELOPMENT EXPECTED THERE LATER THIS
AFTERNOON AND TONIGHT. ALLOWED THE FLOOD ADVISORY FOR THE
SOUTHEAST TO EXPIRE AT 6 AM CDT AS HEAVY RAIN HAS ENDED. THE
HEAVIEST RAIN OVERNIGHT FELL IN STUTSMAN COUNTY...WITH A SMALL
AREA OF 3 TO 4 INCHES BASED ON RADAR ESTIMATES AND OBSERVER REPORTS.
THE APPLE CREEK NEAR MENOKEN IS FORECAST TO RISE TODAY AND MONDAY
IN RESPONSE TO THE RECENT AND FUTURE RAINFALL. NOT EXPECTING THE
LEVEL TO HIT FLOOD STAGE BUT WILL BE MONITORING CLOSELY.
SHORT TERM
(TODAY AND TONIGHT)
ISSUED AT 500 AM CDT SUN MAY 19 2013
FORECAST HIGHLIGHT/CONCERN IN THE SHORT TERM PERIOD WILL BE
RAINFALL AMOUNTS THROUGH TONIGHT.
CURRENTLY...LONG WAVE TROUGH OVER THE WESTERN AND CENTRAL UNITED
STATES. STRONG EMBEDDED S/WV IMPULSE LIFTING NORTH ACROSS WESTERN
SOUTH DAKOTA...VISIBLE ON REGIONAL RADAR AND SATELLITE IMAGERY
WITH CYCLONIC CIRCULATION SITUATED BETWEEN THE BLACK HILLS AND
PIERRE. ASSOCIATED SURFACE TROUGH OVER CENTRAL SOUTH DAKOTA WITH
WRAP AROUND SHOWERS AND STORMS LIFTING NORTH ACROSS SOUTH CENTRAL
AND EASTERN NORTH DAKOTA.
THE LATEST 00Z GFS AND 00Z ECMWF HAVE TRENDED TOWARDS MORE OF A
CONSENSUS FOR THE NEXT 24 HOURS...WITH WIDESPREAD PRECIPITATION
DEVELOPING ACROSS WEST AND CENTRAL NORTH DAKOTA TODAY AND TONIGHT
AND BEYOND AS THE STRONG S/WV IMPULSE NOW OVER WESTERN SOUTH
DAKOTA CLOSES OFF AND REMAINS QUASI-STATIONARY OVER SOUTH
DAKOTA/NORTHERN NEBRASKA THROUGH TONIGHT. MOISTURE WILL CONTINUE
TO WRAP BACK EAST/FEED INTO THE LOW PROVIDING ADDITIONAL RAINFALL
UP TO TWO INCHES...LOCALLY HIGHER...FROM THIS MORNING THROUGH 12Z
MONDAY ACROSS THE SOUTHERN TWO THIRDS OF THE CWA.
WITH ANOTHER INCH OR TWO POSSIBLE MONDAY AND MONDAY NIGHT
(POSSIBLE MORE NORTH)...WE OPTED TO ISSUE A FLOOD WATCH FOR ALL
OF WEST AND CENTRAL NORTH DAKOTA WITH ALREADY 1-2 INCHES OF RAIN
MEASURED SOUTHWEST...SOUTH CENTRAL...AND SOUTHEAST FROM THE PAST
24-48 HOURS...OR FROM BOWMAN TO BISMARCK AND JAMESTOWN. WHILE ALL
BUT THE NORTHWEST AND FAR NORTH CENTRAL IS IN THE WPC DAY 1 (06Z
SUNDAY THROUGH 12Z MONDAY) SLIGHT RISK OF RAINFALL EXCEEDING FLASH
FLOOD GUIDANCE...THE MOST PRONE AREA IS ACROSS MY SOUTHEAST WHERE
LINGERING INSTABILITY WILL BE TODAY AND TONIGHT...AND WHERE HEAVY
RAIN FELL SATURDAY EVENING WITH THE STRONG TO SEVERE STORMS THAT
MOVED THROUGH PARTS OF THE JAMES RIVER BASIN. CONVECTIVE
POTENTIAL DECREASES ELSEWHERE AS WE HEAD INTO MONDAY...BUT STILL
ANTICIPATE HEAVY RAINFALL WITH VERY STRONG FORCING EXPECTED. WITH
MODELS FLUCTUATING THE PAST COUPLE OF DAYS...FELT IT TO BE SAFER
TO INCLUDE THE ENTIRE AREA IN THE WATCH IN CASE OF FURTHER
POSITION CHANGES OF THE UPPER LOW.
LONG TERM
(MONDAY THROUGH SATURDAY)
ISSUED AT 500 AM CDT SUN MAY 19 2013
THE MAIN FORECAST ISSUE THROUGH THE LONG TERM PERIOD IS CONTINUED
HEAVY RAIN AND POTENTIAL FOR FLOODING. THE LATEST SUITE OF 19/00Z
MODELS IS COMING INTO BETTER AGREEMENT REGARDING THE TRACK OF THE
CLOSED UPPER LOW THROUGH THE REGION. THE CONSENSUS INDICATES A
PROLONGED PERIOD OF MODERATE TO HEAVY RAIN CONTINUING MONDAY INTO
TUESDAY...IMPACTING MOST IF NOT ALL OF WESTERN AND CENTRAL NORTH
DAKOTA. ADDITIONAL RAINFALL AMOUNTS UP TO 4 INCHES ARE EXPECTED. IN
ADDITION TO FLOODING CONCERNS ALONG SMALL STREAMS...AND LOW LYING
AREAS...WILL BE MONITORING RIVERS CLOSELY THIS WEEK...ESPECIALLY THE
FASTER RESPONDING POINTS SUCH AS APPLE CREEK NEAR MENOKEN. SHOWERS
ARE EXPECTED TO BECOME MORE SCATTERED TUESDAY NIGHT INTO WEDNESDAY.
ALTHOUGH SOME THUNDERSTORMS WILL BE POSSIBLE MONDAY INTO
TUESDAY...NO SEVERE WEATHER IS EXPECTED. THE NEXT BEST CHANCE OF
RAIN WILL BE LATE FRIDAY INTO SATURDAY. EXPECT COOL TEMPS THROUGH
TUESDAY...WITH A GRADUAL WARMING TREND INTO THE WEEKEND.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z MONDAY)
ISSUED AT 112 AM CDT SUN MAY 19 2013
SLOW MOVING LOW PRESSURE OVER NORTHEAST SOUTH DAKOTA WILL IMPACT
THE AREA WITH STRATUS...FOG...RAIN AND THUNDERSTORMS THROUGH THE
12 UTC TAF CYCLE. MVFR TO IFR CONDITIONS IN MODERATE RAIN AND
STRATUS FOR KBIS...KMOT AND KDIK. FOR KJMS...SCATTERED SHOWERS AND
THUNDERSTORMS RE-DEVELOPING THIS AFTERNOON AND EVENING WITH IFR
CONDITIONS IN STRATUS THIS MORNING IMPROVING TO MVFR. FOR
KISN...VFR BECOMING MVFR IN RAIN AND STRATUS THIS AFTERNOON.
NORTHERLY WINDS GUSTS OF 30-35 KTS POSSIBLE AT KDIK...KMOT AND
KISN LATE THIS AFTERNOON THROUGH TONIGHT.
.HYDROLOGY ..
ISSUED AT 950 AM CDT SUN MAY 19 2013
A FLOOD WATCH REMAINS IN EFFECT FOR ALL OF WESTERN AND CENTRAL
NORTH DAKOTA THROUGH MONDAY NIGHT.
SEVERAL FORECAST POINTS ACROSS THE JAMES AND MISSOURI RIVER BASINS
MAY RISE ABOVE FLOOD STAGE IN THE NEXT 24-48 HOURS. WILL HOLD OFF ON
ANY WARNINGS FOR NOW TO SEE HOW THE RIVERS AND STREAMS RESPOND AS
FORECASTS ARE HEAVILY DEPENDENT UPON RAINFALL OVER THE NEXT 48
HOURS. HOWEVER...FOR THE APPLE CREEK NEAR MENOKEN AND THE BEAVER
CREEK AT LINTON...MINOR FLOODING MAY BE POSSIBLE BY MONDAY
EVENING. FOR THE CANNONBALL RIVER NEAR BREIEN...MINOR FLOODING IS
POSSIBLY BY WEDNESDAY MORNING. FOR THE PIPESTEM CREEK NEAR
PINGREE...MINOR FLOODING IS POSSIBLE BY MONDAY MORNING...WITH
MODERATE FLOODING POSSIBLE THEREAFTER. FOR THE JAMES RIVER NEAR
GRACE CITY...MINOR FLOODING MAY BE POSSIBLE BY WEDNESDAY MORNING.
BIS WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH THROUGH TUESDAY MORNING FOR NDZ001>005-009>013-
017>023-025-031>037-040>048-050-051.
UPDATE...AYD
SHORT TERM...NH
LONG TERM...RK
AVIATION...NH
HYDROLOGY...AYD
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