Archive for June 2007

Dewpoint vs. Humidity

Posted: Thursday, June 28, 2007 at 4:30 pm
By: Administrator
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I often hear from people who want to see the relative humidity on TV. We do show it…but very rarely and mostly because the farmers want to know if they can make hay in the afternoon!. But unless your a farmer, meteorologist, or engineer, relative humidity is not critical to our everyday lives.
Here’s the official definition:
Relative humidity is the ratio of the amount of moisture in the air to the maximum amount of moisture the air could have. It is defined as the vapor pressure (or mixing ratio) divided by the saturation vapor pressure (or saturation mixing ratio).
I’m not here to teach a weather class…so I won’t explains saturation vapor pressure :) However, here’s a little easier way to thinking about it. Imagine looking a glass of water sitting on table. For arguments sake, we’ll say a full glass of water represents 100% relativity humidity at 40 degrees…half-full is 50% relative humidity. OK…so what?? Put the glass of water aside and replace it with a 5 gallon bucket. Now, fill it half full. That’s still 50% relative humidity. But is it the same amount as in the glass of water? Of course not. This represents the relative humidity at 80 degrees. Big difference wouldn’t you say? The percentage tells me nothing about how is "feels"…and that’s the point of this blog. If you want to know how muggy the weather really is…watch the dewpoint.
Here’s the official definition:
Dewpoint is the temperature air will reach saturation when air cools and maintains a constant pressure and constant moisture content. To find dewpoint, the temperature and wet bulb temperature need to be known.
In other words, the temperature can’t cool below the dewpoint and is an absolute measure of humidity. This calculation involves the wet bulb temperature…another variable we measure in meteorology. This information become useful once we condense it into dewpoint…and people like you and I can really know how it feels outside. Anytime the dewpoint is climbs above 60, it starts to feel humid. When it climbs above 70, it feels really uncomfortable. And when it’s above 80….that’s really bad. We get dewpoints in the 80s once in awhile in KELOLAND…mainly in NW IA during July in the middle of corn field. Some people outside the midwest think that’s not possible, but it’s true! Corn and evapotransporation can add excessive moisture into the air. That’s probably more that you wanted to know, but feel free to add your comments!
BK
 

Hot Monday Afternoon

Posted: Monday, June 25, 2007 at 2:50 pm
By: Administrator
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It’s a hot and windy afternoon in KELOLAND.  It’s already 104 in Phillip with strong south winds of 20-40 mph.  Scattered t-storms are possible along a cold front late this afternoon currently moving into the northwest part of the state.  Severe weather is possible along the North Dakota border and in the Black Hills region late this afternoon and this evening.  Otherwise, try to stay cool!  The cold front will bring relief to most of the region tomorrow and Wednesday.-BK

June21st Weather

Posted: Thursday, June 21, 2007 at 5:55 pm
By: Administrator
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It looks like scattered t-storm (some severe) will continue through the evening in western SD including the Black Hills.A stationary front remains parked over eastern SD from near Winner to Huron and Brookings.  The black dotted line in Nebraska represents the outflow boundary from the morning storms.  That may play a role in where t-storms redevelop later this evening…a trend we will be watching.Supercell t-storms are forming in two clusters in western SD… in the southern Black Hills and also south of Dupree.   Severe t-storm warnings were issued for both for large hail.  A tornado watch is in effect until midnight for the counties shaded in red.BK (5:58pm)

Weather Update

Posted: Wednesday, June 13, 2007 at 4:57 pm
By: Administrator
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Weather Update-5pmMore moderate rainfall is likely tonight and tomorrow.  Another 1" is possible, but the threat of additional flash flooding has diminished.Brian Karstens

Weather Update

Posted: Wednesday, June 13, 2007 at 11:34 am
By: Administrator
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Weather Update: Wednesday, June 13th (11:30am)A slow moving cold front and trough of low pressure will continue to focus heavy showers and thunderstorms the next 24 hours over eastern SD.  A flash flood watch remains in effect for much of the region.BK

Summer Weather (June 10-13)

Posted: Sunday, June 10, 2007 at 11:45 am
By: Administrator
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With reports of golf ball size hail SE of Marion, this morning’s Severe Thunderstorm in Turner County may be a taste of what’s to come over the next several days…
 
The hot and humid weather is set to return today, and by the way KELOLAND looks…expect the humidity to ‘stick’ around.  Take a trip around South Dakota and you’ll notice how green everything has become as the crops have emerged and the grass continues to grow.  I’ve heard nothing but good comments about central and western South Dakota on how green the land has become over the past several weeks.  The green ground and growing crops will continue to lead to more humidity; welcome to summer.
 
We’ll interact with the humidity through this week with a series of scattered showers and storms over the next several days.  Each day will also bring in severe weather (much like this morning’s hail reports in Turner County).  Feel free to add any weather reports in the comments section below…

Storm Reports

Posted: Thursday, June 7, 2007 at 4:21 am
By: Administrator
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Here is a list of all the storm reports so far from the National Weather Service as of 7:30am0737 PM     TSTM WND GST     18 S PIERRE             44.11N 100.32W  06/06/2007  M60.00 MPH       LYMAN              SD   MESONET                         FT PIERRE RAWS SITE    0745 PM     TSTM WND GST     RELIANCE                43.88N 99.60W   06/06/2007  E60.00 MPH       LYMAN              SD   EMERGENCY MNGR      0820 PM     TSTM WND GST     3 NW MISSION RIDGE      44.72N 100.83W  06/06/2007  M65.00 MPH       STANLEY            SD   CO-OP OBSERVER      0855 PM     HAIL             MOBRIDGE                45.54N 100.44W  06/06/2007  E0.88 INCH       WALWORTH           SD   PUBLIC                          REPORTED BY COCORAHS OBSERVER    0905 PM     HAIL             8 N GLENHAM             45.65N 100.27W  06/06/2007  E0.88 INCH       CAMPBELL           SD   CO-OP OBSERVER      0945 PM     HAIL             CRAVENS CORNER          45.45N 98.93W   06/06/2007  M1.00 INCH       EDMUNDS            SD   LAW ENFORCEMENT                 NICKEL AND QUARTER SIZE HAIL WITH 40 TO 45 MPH WINDS.    0133 AM     NON-TSTM WND GST HAYTI                   44.66N 97.20W   06/07/2007  M59.00 MPH       HAMLIN             SD   EMERGENCY MNGR                  POWER LINES DOWN AND SEVERAL TREES DOWN AND/OR UPROOTED.               SOME STRUCTURAL DAMAGE DUE TO FALLING TREES.    0235 AM     NON-TSTM WND GST ORTONVILLE              45.30N 96.44W   06/07/2007  M59.00 MPH       BIG STONE          MN   AWOS    PRELIMINARY LOCAL STORM REPORTNATIONAL WEATHER SERVICE SIOUX FALLS SD129 AM CDT THU JUN 07 2007..TIME…   …EVENT…      …CITY LOCATION…     …LAT.LON…..DATE…   ….MAG….      ..COUNTY LOCATION..ST.. …SOURCE….            ..REMARKS..0128 AM     HAIL             STORDEN                 44.04N 95.32W06/07/2007  E1.75 INCH       COTTONWOOD         MN   TRAINED SPOTTER
000
NWUS53 KFSD 070427
LSRFSD

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1127 PM CDT WED JUN 06 2007

..TIME… …EVENT… …CITY LOCATION… …LAT.LON…
..DATE… ….MAG…. ..COUNTY LOCATION..ST.. …SOURCE….
..REMARKS..

1127 PM TSTM WND GST 3 W MARION 43.42N 97.32W
06/06/2007 E60 MPH TURNER SD TRAINED SPOTTER

000
NWUS53 KFSD 070418
LSRFSD

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1118 PM CDT WED JUN 06 2007

..TIME… …EVENT… …CITY LOCATION… …LAT.LON…
..DATE… ….MAG…. ..COUNTY LOCATION..ST.. …SOURCE….
..REMARKS..

1116 PM TSTM WND GST 5 S FREEMAN 43.28N 97.43W
06/06/2007 E60 MPH HUTCHINSON SD LAW ENFORCEMENT

000
NWUS53 KFSD 070407
LSRFSD

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1107 PM CDT WED JUN 06 2007

..TIME… …EVENT… …CITY LOCATION… …LAT.LON…
..DATE… ….MAG…. ..COUNTY LOCATION..ST.. …SOURCE….
..REMARKS..

1107 PM TSTM WND GST OLIVET 43.24N 97.67W
06/06/2007 E60 MPH HUTCHINSON SD TRAINED SPOTTER

000
NWUS53 KFSD 070347
LSRFSD

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1047 PM CDT WED JUN 06 2007

..TIME… …EVENT… …CITY LOCATION… …LAT.LON…
..DATE… ….MAG…. ..COUNTY LOCATION..ST.. …SOURCE….
..REMARKS..

1046 PM TSTM WND GST TRIPP 43.22N 97.97W
06/06/2007 E60 MPH HUTCHINSON SD TRAINED SPOTTER

000
NWUS53 KFSD 070333
LSRFSD

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1033 PM CDT WED JUN 06 2007

..TIME… …EVENT… …CITY LOCATION… …LAT.LON…
..DATE… ….MAG…. ..COUNTY LOCATION..ST.. …SOURCE….
..REMARKS..

1030 PM TSTM WND GST WAGNER 43.08N 98.30W
06/06/2007 E65 MPH CHARLES MIX SD CO-OP OBSERVER

BRANCHES DOWN

000
NWUS53 KFSD 070333
LSRFSD

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1033 PM CDT WED JUN 06 2007

..TIME… …EVENT… …CITY LOCATION… …LAT.LON…
..DATE… ….MAG…. ..COUNTY LOCATION..ST.. …SOURCE….
..REMARKS..

1030 PM TSTM WND GST AVON 43.01N 98.06W
06/06/2007 E70 MPH BON HOMME SD EMERGENCY MNGR

000
NWUS53 KABR 070259
LSRABR

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ABERDEEN SD
959 PM CDT WED JUN 06 2007

..TIME… …EVENT… …CITY LOCATION… …LAT.LON…
..DATE… ….MAG…. ..COUNTY LOCATION..ST.. …SOURCE….
..REMARKS..

0945 PM HAIL CRAVENS CORNER 45.45N 98.93W
06/06/2007 M1.00 INCH EDMUNDS SD LAW ENFORCEMENT

NICKEL AND QUARTER SIZE HAIL WITH 40 TO 45 MPH WINDS.

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000
NWUS53 KUNR 070242
LSRUNR

PRELIMINARY LOCAL STORM REPORT…SUMMARY
NATIONAL WEATHER SERVICE RAPID CITY SD
841 PM MDT WED JUN 06 2007

..TIME… …EVENT… …CITY LOCATION… …LAT.LON…
..DATE… ….MAG…. ..COUNTY LOCATION..ST.. …SOURCE….
..REMARKS..

0235 PM TORNADO 10 SW GILLETTE 44.19N 105.64W
06/06/2007 CAMPBELL WY PUBLIC

NUMEROUS PUBLIC REPORTS OF A TORNADO ON THE
GROUND…POSSIBLY MORE THAN ONE. TORNADOES ARE MAKING
REPEATED TOUCHDOWNS. RELAYED BY CAMPBELL COUNTY EMERGENCY
MANAGER.

0245 PM TORNADO GILLETTE 44.29N 105.50W
06/06/2007 CAMPBELL WY PUBLIC

TORNADO ON THE SOUTHWEST SIDE OF GILLETTE

0255 PM HAIL GILLETTE 44.29N 105.50W
06/06/2007 E1.75 INCH CAMPBELL WY EMERGENCY MNGR

WEST SIDE OF GILLETTE

0300 PM HAIL GILLETTE 44.29N 105.50W
06/06/2007 E1.00 INCH CAMPBELL WY EMERGENCY MNGR

0311 PM TORNADO 9 SW KYLE 43.33N 102.31W
06/06/2007 SHANNON SD STORM CHASER

NUMEROUS REPORTS OF TORNADO ON GROUND SOUTH OF KYLE.
BASED ON PRELIMINARY REPORTS AND RADAR DATA…TORNADO
TOUCHED DOWN ABOUT 311 PM 9 MILES SOUTHWEST OF KYLE AND
LIFTED AT 335 PM 6 MILES SOUTHEAST OF KYLE. REPORTS OF
POWER LINES DOWN ON AMERICAN HORSE ROAD.

0400 PM HAIL 2 S POTATO CREEK 43.51N 101.99W
06/06/2007 E0.88 INCH JACKSON SD TRAINED SPOTTER

0425 PM TSTM WND GST 5 NE PORCUPINE 43.28N 102.26W
06/06/2007 M67.00 MPH SHANNON SD MESONET

0450 PM TORNADO 5 SW KADOKA 43.78N 101.58W
06/06/2007 JACKSON SD NWS EMPLOYEE

RAIN WRAPPED TORNADO LASTED 5 MINUTES

0510 PM TSTM WND GST N COLONY 44.87N 104.16W
06/06/2007 E60.00 MPH CROOK WY TRAINED SPOTTER

0510 PM HAIL N COLONY 44.87N 104.16W
06/06/2007 E0.88 INCH CROOK WY TRAINED SPOTTER

0510 PM HAIL 1 W KADOKA 43.83N 101.53W
06/06/2007 E0.88 INCH JACKSON SD LAW ENFORCEMENT

0510 PM TSTM WND GST 14 SSE KADOKA 43.64N 101.40W
06/06/2007 E60.00 MPH JACKSON SD TRAINED SPOTTER

60 MPH WINDS LASTED 15 MINUTES

0520 PM TSTM WND GST 3 S VETAL 43.17N 101.37W
06/06/2007 E70.00 MPH BENNETT SD PUBLIC

0525 PM NON-TSTM WND GST 6 W PARMELEE 45.02N 101.23W
06/06/2007 M67.00 MPH DEWEY SD MESONET

0530 PM TSTM WND GST MISSION 43.31N 100.66W
06/06/2007 M59.00 MPH TODD SD MESONET

0530 PM TSTM WND GST 3 SW PARMELEE 43.30N 101.06W
06/06/2007 E60.00 MPH TODD SD TRAINED SPOTTER

0530 PM TSTM WND GST WHITE RIVER 43.57N 100.74W
06/06/2007 E70.00 MPH MELLETTE SD LAW ENFORCEMENT

TREES DOWN IN WHITE RIVER. 70 MPH WINDS LASTED 20
MINUTES.

0535 PM HAIL 2 E STONEVILLE 44.74N 102.61W
06/06/2007 E1.00 INCH MEADE SD NWS EMPLOYEE

0540 PM TSTM WND GST 18 NNW BELLE FOURCHE 44.91N 103.99W
06/06/2007 E60.00 MPH BUTTE SD TRAINED SPOTTER

0556 PM TSTM WND GST 17 NNW MIDLAND 44.30N 101.28W
06/06/2007 E70.00 MPH HAAKON SD TRAINED SPOTTER

0600 PM TSTM WND GST 6 NE WOOD 43.55N 100.39W
06/06/2007 E60.00 MPH MELLETTE SD TRAINED SPOTTER

WINDS AT LEAST 60 MPH

0610 PM TSTM WND GST 11 ENE MILESVILLE 44.52N 101.47W
06/06/2007 E60.00 MPH HAAKON SD TRAINED SPOTTER

0610 PM HAIL 11 ENE MILESVILLE 44.52N 101.47W
06/06/2007 E0.75 INCH HAAKON SD TRAINED SPOTTER

0620 PM TSTM WND GST 10 NNW IDEAL 43.68N 99.99W
06/06/2007 E60.00 MPH TRIPP SD TRAINED SPOTTER

0653 PM TSTM WND GST PHILIP 44.05N 101.67W
06/06/2007 M58.00 MPH HAAKON SD ASOS

MEASURED BY THE PHILIP ASOS

&&

$

WFO UNR

000
NWUS53 KFSD 070216
LSRFSD

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
915 PM CDT WED JUN 06 2007

..TIME… …EVENT… …CITY LOCATION… …LAT.LON…
..DATE… ….MAG…. ..COUNTY LOCATION..ST.. …SOURCE….
..REMARKS..

0852 PM HAIL 10 SW WESSINGTON SPRING 43.98N 98.71W
06/06/2007 E0.75 INCH JERAULD SD TRAINED SPOTTER

Severe Weather Discussion-9am

Posted: Wednesday, June 6, 2007 at 8:21 am
By: Administrator
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It looks like a busy day for us in the stormcenter.  We have a moderate risk of severe weather over about the eastern 2/3rds of KELOLAND late this afternoon and tonight .The map below shows a more detailed timing of the severe weather and what to expect.  It looks like storms will develop in central and southcentral SD first along a dryline.  These storms will be supercells capable of producing large hail greater than golf ball size, winds up to 80mph, and isolated tornadoes.  The threat of severe weather will shift east of the Missouri River through the evening, with supercells merging into clusters with the potential for a signifcant squall line developing in our eastern counties late tonight.  The could produce high winds over 70-80mph over several counties.  We can’t rule out tornadoes after dark either…with the potential for a signficant tornado.  Obviously, that’s a threat we’ll be watching through the evening.  Stay tuned for more updates as the situation develops.BK