Monday, June 22, 2015

Dwindling Daylight; Nearly Perfect Tuesday Ahead



Atmospheric Lag
By Todd Nelson

The longest day of the year occurred 2 days ago on the Summer Solstice when the sun's most direct rays were shining over the Tropic of Cancer. Since then, we've actually lost 10 seconds of daylight! The good news is that we still have nearly 15 and 1/2 hours of daylight in Minneapolis through early July.

Even though we are losing daylight, our average temperature continues to rise through mid July thanks to the atmospheric or seasonal lag. Because our atmosphere is largely made up of water, it takes a while for it to warm up or cool down even after maximum or minimum times of solar insolation.

Temperatures today will be near average for late June with highs near 80 degrees. A light breeze and mostly sunny skies will make for a nearly perfect early summer day. Another impulse of energy arrives tomorrow with spotty showers and storms, mainly across southern Minnesota. Weather conditions stay a little on the unsettled side much of the rest of the week as isolated rumbles may be possible each afternoon through the weekend. Keep in mind that no day looks like a washout.

I still don't see any heat waves brewing. Until then, enjoy the summer breeze!
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MONDAY NIGHT: Mostly clear, not as breezy. Low: 61. Winds: NW 5-15.

TUESDAY: Plenty of sunshine, pleasant with a slight dip in humidity. High: 81

TUESDAY NIGHT: Partly cloudy, nothing rough. Low: 63.

WEDNESDAY: More clouds, thunder develops late. High: 81

THURSDAY: Spotty afternoon rumbles. Wake-up: 64. High: 78

FRIDAY: Isolated PM T-shower possible. Wake-up: 63. High: 80

SATURDAY: Dry start, late day rumble. Wake-up: 62. High: 81

SUNDAY: More humid, scattered PM storms. Wake-up: 63. High: 81.

MONDAY: Sun returns, still mild. Wake-up: 65. High: 82.
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This Day in Weather History
June 23rd
2002: Just a few weeks after torrential rains hit the area, another round of heavy rain hit northern Minnesota. This time up to eight inches fell in a two-day period in small parts of Mahnomen and St. Louis Counties.
1992: Chilly air across Minnesota with a high of 48 at the Duluth Harbor and 52 at Grand Marais.
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Average High/Low for Minneapolis
June 23rd
Average High: 81 (Record: 99 set in 1937)
Average Low: 61 (Record: 44 set in 1972)
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Sunrise/Sunset Times for Minneapolis
June 23rd
Sunrise: 5:27am
Sunset: 9:03pm
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Moon Phase for June 23rd at Midnight
0.2 Days Before First Quarter


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Minneapolis Temperature Trend
Temperatures look to stay near average over the next several days (near 80F) with lows staying close to near average as well (near 60F). At this point, I don't see any major cool downs or heat waves in the near future.


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Tuesday Weather Outlook
Tuesday looks like a very comfortable day with highs near 80F, light winds and plenty of blue sky. Tuesday will be an almost perfect early summer day!


Tuesday Weather Outlook
Much of the region will be dry and sunny with the exception being along the international border where a few spotty showers may be possible.


Minnesota Rainfall Potential
Rainfall potential through doesn't look all that impressive across Minnesota. Some of the heaviest looks to stay along the international border with pockets of near 0.5" possible through 7pm Wednesday.


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Monday Morning Recap:
Tis the season for overnight thunderstorm activity with damaging winds being the primary threat. Sunday night/early Monday morning featured a complex of thunderstorms that was responsible for several damaging wind reports with wind speeds reaching 95mph in Sheldon, IA. Take a look at what the radar looked like early Monday morning.


Thunderstorm wind gusts were responsible for this overturned semi near Canton, SD early this morning. Sioux Falls, SD had wind gusts topping 80mph!


Here is the 95mph wind report from Sheldon, IA located in the northwest part of the state. Note the report states an airplane hangar was destroyed with damage occurring to planes.


Hail, high wind and damaging wind reports stretched from eastern South Dakota through Minnesota, Iowa and eventually into Wisconsin and Illinois. Note the 95mph wind gust report in northwest IA.


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National Weather Outlook
The storm system that pushed through the Upper Midwest earlier this week will be responsible for scattered thunderstorms across parts of the Northeast and Ohio Valley on Tuesday, some of which could be on the strong to severe side. Meanwhile, an area of high pressure move in to the Midwest on Tuesday making for a beautiful day. However, another impulse of energy pushes into the region by midweek.


5 Day Precipitation Outlook
According to NOAA's HPC, the heaviest rainfall over the next 5 days looks to fall over parts of the Ohio and Tennessee Valley through the Mid-Atlantic States. Meanwhile, areas in the Western U.S. look to stay mostly dry through Saturday.


Severe Threat Tuesday
...SUMMARY... SEVERE THUNDERSTORMS WITH LARGE HAIL AND DAMAGING WIND GUSTS ARE EXPECTED FROM PORTIONS OF NEW ENGLAND INTO THE CENTRAL APPALACHIANS AND OHIO VALLEY. FARTHER WEST...OTHER SEVERE STORMS WITH LARGE HAIL AND ISOLATED WIND DAMAGE WILL ALSO BE POSSIBLE IN THE CENTRAL AND NORTHERN HIGH PLAINS FROM LATE TUESDAY AFTERNOON THROUGH THE EVENING. ...NORTHEAST STATES... MCS WILL BE ONGOING EARLY TUESDAY MOST LIKELY OVER PORTIONS OF NEW ENGLAND GENERALLY ALONG AND NORTH OF A WARM FRONT THAT IS EXPECTED TO EXTEND FROM SRN NH AND VT NWWD INTO SRN QUEBEC. THE ATMOSPHERE IS EXPECTED TO DESTABILIZE IN WAKE OF AND UPSTREAM OF THE MCS AS RICHER LOW-LEVEL MOISTURE IS ADVECTED NEWD THROUGH WARM SECTOR IN ADVANCE OF A SEWD ADVANCING COLD FRONT. SOME BREAKS IN RESIDUAL LOW CLOUDS ARE EXPECTED WITH MLCAPE UP TO 1500 J/KG POSSIBLE IN THIS REGION. STORMS ARE EXPECTED TO REDEVELOP ALONG AND JUST AHEAD OF THE COLD FRONT FROM NEWD ENGLAND SWWD INTO THE NERN U.S. AND MID ATLANTIC. IMPRESSIVE DEEP LAYER WINDS ASSOCIATED WITH A PROGRESSIVE SHORTWAVE TROUGH WILL SPREAD ACROSS THE NRN PORTIONS OF THE WARM SECTOR WITH 40-50 KT 0-6 KM SHEAR SUPPORTIVE OF ORGANIZED STORMS INCLUDING SUPERCELLS AND BOWING SEGMENTS. WIND PROFILES WILL BECOME WLY UNIDIRECTIONAL SOUTH OF WARM FRONT SUGGESTING PRIMARY THREAT WILL BE LARGE HAIL AND DAMAGING WIND. HOWEVER...AN EXCEPTION WILL BE OVER NEW ENGLAND WHERE A THREAT FOR A FEW TORNADOES WILL BE CONDITIONAL UPON SUFFICIENT DESTABILIZATION IN VICINITY OF THE CONVECTIVELY ENHANCED WARM FRONT. ...MID ATLANTIC THROUGH SRN OH VALLEY TN VALLEY AND NC... MUCH OF THIS REGION WILL RESIDE ON SRN PERIPHERY OF STRONGER WINDS ALOFT WHERE VERTICAL SHEAR WILL SUPPORT PRIMARILY MULTICELL MODES. STRONG DIABATIC WARMING AND DESTABILIZATION OF THE BOUNDARY LAYER WILL LIKELY PROMOTE REDEVELOPMENT OF STORMS ALONG THE CNTRL/SRN APPALACHIANS AND ALONG/AHEAD OF THE SEWD ADVANCING COLD FRONT. ISOLATED DAMAGING WIND AND HAIL WILL BE THE MAIN THREATS FROM AFTERNOON THROUGH EARLY EVENING. ...CNTRL AND NRN HIGH PLAINS... MODIFIED CP AIR WITH DEWPOINTS IN THE 50S WILL RETURN NWD THROUGH THE HIGH PLAINS BENEATH STEEP LAPSE RATES IN WAKE OF RETREATING SFC RIDGE. THIS WILL CONTRIBUTE TO AN AXIS OF 500-1500 J/KG MLCAPE. MUCH OF THIS REGION WILL RESIDE BENEATH ZONE OF FASTER WLY ALOFT RESULTING IN 40-50 KT EFFECTIVE SHEAR. ISOLATED TO WIDELY SCATTERED STORMS ARE EXPECTED TO DEVELOP OVER THE HIGHER TERRAIN AND SPREAD EWD INTO THE HIGH PLAINS. SUPERCELLS WITH LARGE HAIL AND DAMAGING WIND APPEAR TO BE THE MAIN THREATS. MORE NUMEROUS STORMS ARE EXPECTED OVERNIGHT OVER THE CNTRL PLAINS WHERE A STRENGTHENING LLJ WILL AUGMENT ASCENT NORTH OF A STALLED FRONT. POTENTIAL WILL EXIST FOR SOME OF THIS ACTIVITY TO GROW UPSCALE POSING A RISK FOR LARGE HAIL AND DAMAGING WIND.


Severe Threat Wednesday

...SUMMARY... A SEVERE THREAT IS EXPECTED TO DEVELOP FROM PARTS OF THE NORTHERN PLAINS EAST SOUTHEASTWARD INTO THE UPPER MIDWEST ON WEDNESDAY. A TORNADO THREAT ALONG WITH LARGE HAIL AND DAMAGING WIND GUSTS WILL BE POSSIBLE DURING THE AFTERNOON AND EVENING WITH THE GREATEST POTENTIAL FOR SEVERE STORMS LOCATED OVER PARTS OF THE UPPER MIDWEST. ...MID-MO VALLEY/UPPER MIDWEST... AN UPPER-LEVEL TROUGH IS FORECAST TO MOVE INTO THE NRN PLAINS ON WEDNESDAY. AT THE SFC...A LOW IS FORECAST TO MOVE INTO THE MID MO VALLEY WITH A WARM FRONT LOCATED FROM NRN IA SEWD INTO NRN IL. A VERY MOIST AIRMASS SHOULD BE IN PLACE FROM THE SFC LOW SEWD ACROSS THE MID MS VALLEY WITH SFC DEWPOINTS IN THE LOWER 70S F. AS SFC TEMPS WARM ALONG THIS CORRIDOR...MODERATE TO STRONG INSTABILITY SHOULD BE IN PLACE BY MIDDAY. ALTHOUGH CELL INITIATION SEEMS POSSIBLE NEAR THE SFC LOW DURING THE EARLY AFTERNOON...WARM TEMPERATURES AT MID-LEVELS MAY INHIBIT DEEP CONVECTION FROM DEVELOPING UNTIL LATE AFTERNOON OR EARLY EVENING. CONVECTIVE COVERAGE WILL PROBABLY BE GREATEST ALONG THE WARM FRONT WITH THE ACTIVITY MOVING TO THE COOL SIDE OF THE BOUNDARY. DISCRETE CELL FORMATION WILL ALSO BE POSSIBLE AS THE CAP BECOMES WEAKER DURING THE LATE AFTERNOON TO THE SOUTH OF THE SFC LOW ACROSS PARTS OF IA WHERE INSTABILITY AND LOW-LEVEL CONVERGENCE IS FORECAST TO BE MAXIMIZED. NAM FORECAST SOUNDINGS FOR DES MOINES IA SEWD TO NEAR SPRINGFIELD IL AT 00Z/THURSDAY SHOW IMPRESSIVE THERMODYNAMIC PROFILES WITH MLCAPE IN THE 3000 TO 4000 J/KG RANGE AND 0-6 KM SHEAR OF 35 TO 40 KT. THIS SHOULD SUPPORT SUPERCELLS AND LARGE HAIL WITH CELLS THAT REMAIN DISCRETE AND HAVE ACCESS TO THE STRONGEST INSTABILITY. A TORNADO THREAT WILL BE POSSIBLE WITH SUPERCELLS THAT INTERACT WITH THE WARM FRONT. A WIND DAMAGE THREAT MAY ALSO DEVELOP WITH SUPERCELLS AND/OR BOWING LINE SEGMENTS. ...NRN PLAINS... AN UPPER-LEVEL TROUGH IS FORECAST TO MOVE EWD INTO THE NRN PLAINS ON WEDNESDAY AS A COLD FRONT ADVANCES SEWD ACROSS ERN SD AND NRN NEB. THE POST-FRONTAL AIRMASS SHOULD BE MOIST WITH SFC DEWPOINTS REMAINING IN THE 60S F. THIS SHOULD RESULT IN MODERATE INSTABILITY ACROSS THE PARTS OF THE NRN PLAINS BY AFTERNOON. ISOLATED CELL INITIATION WILL BE POSSIBLE DURING THE LATE AFTERNOON IN THE POST-FRONTAL AIRMASS AS THE SHORTWAVE TROUGH MOVES ACROSS THE REGION. FORECAST SOUNDINGS AT 21Z IN CNTRL SD SHOW SBCAPE AROUND 1500 J/KG WITH 50 KT OF 0-6 KM SHEAR BUT HAVE POOR LAPSE RATES. THIS ENVIRONMENT COULD BE ENOUGH FOR MARGINALLY SEVERE STORMS WITH POTENTIAL FOR HAIL AND STRONG WIND GUSTS. ...CNTRL APPALCHIANS/NORTH CAROLINA... A QUASI-STATIONARY FRONT IS FORECAST TO BE IN PLACE FROM THE OH VALLEY SEWD INTO THE CAROLINAS ON WEDNESDAY WITH SFC DEWPOINTS NEAR AND TO THE SOUTH OF THE BOUNDARY IN THE UPPER 60S AND LOWER 70S F. THIS SHOULD RESULT IN THE DEVELOPMENT OF MODERATE TO STRONG INSTABILITY WITH THE INITIATION OF ISOLATED THUNDERSTORMS POSSIBLE ALONG THE FRONT DURING THE AFTERNOON. ALTHOUGH LARGE-SCALE ASCENT IS FORECAST TO BE WEAK...THE MAGNITUDE OF INSTABILITY COMBINED WITH ADEQUATE DEEP-LAYER SHEAR MAY BE ENOUGH FOR MARGINALLY SEVERE WIND GUSTS.


Large Wildfires in Alaska
Several large wildfires continue in Alaska as warm and dry weather conditions have prevailed. There are currently 4 wildfires that have consumed 10,000 to 20,000 plus acres, the biggest of which is the Chisana River 2 Fire that has consumed nearly 30,000 acres as of late Sunday.


(Images courtesy Inciweb)

Northern Lights Potential

"A coronal mass ejection (CME) is heading directly for Earth. It left the sun during the early hours of June 21st, and is expected to sweep up one or two lesser CMEs already en route, before it reaches Earth sometime on June 22nd."

"NOAA forecasters estimate a 90% chance of polar geomagnetic storms when the CME arrives. This doesn't mean that a major space weather event is in the offing. The storm could be mild. It all depends on how the magnetic field of the CME connects to the magnetic field of Earth at the time of impact. According to NOAA, there's only a 10% chance of nothing happening, so stay tuned."




Thanks for checking in and have a great rest of your week! Don't forget to follow me on Twitter @TNelsonWX

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