Weather pictures & report of January 5-11 2009

 

Snow related to cold front resulted in a week old fashion winter weather


Synopsis: at 500 hPa: on January 5, a sharpening upper trough with its related waving cold front passed Belgium from north to south giving light to moderate falls of snow for more than 12 hours. With slightly subzero temperatures, snow accumulated between 1 and 12 cm over entire Belgium except for the extreme western parts. Afterwards temperatures remained subzero for almost a week. Below a pictorial report, all pics have been taken at Kampenhout or Steenokkerzeel in local time (CET). 

 

Analysis of the mean sea level pressure with fronts of 05/01/2009 at 0100 CET: a waving cold front over mid Holland moved southwards. (Source chart: Met Office - UKMO)

 

Radar sequence between 0540-0820 CET. It shows the movement of the most intense belt of wintry precipitation. (Source radar picture: Belgocontrol)

 

Satellite sequence (infra-red channel) between 0700-0845 CET. The entire country covered by thick cloudiness, while breaks appear over northern Holland. (Source: Meteosat via Sat24.com)

 

 

Satellite combined with radar images of 0800 CET, with calculation of type of precipitation. Clearly visible over the eastern parts of Belgium more intense precipitation was falling. (Source: DWD)

 

Satellite sequence (visible channel) between 1030-1230 CET. The breaks reached southern parts of Holland, giving a first glimp of the snow on the ground over this part of Holland. (Source: Meteosat via Sat24.com)

 

Observed mean sea level surface chart of 0900 CET with the so called 'plots': the small low (waving cold front), induced wintry precipitation for hours.  (Source map: Meteocentre).

 

Observed upper air chart at 300 hPa of 1300 CET, airflow veered to the NE.  (Source map: DWD).

 

Observed upper air chart at 500 hPa of 1300 CET, axis of the trough passed Belgium. Furthermore a classic Omega pattern for severe winter weather: ridge axis over the Atlantic and trough axis over the continent. (Source map: DWD).

 

Observed upper air chart at 850 hPa of 1300 CET, also here the airflow veered to the NE introducing temperatures of -10°C and below.  (Source map: DWD).

 

Forecasted sounding of Maastricht at 0100 CET. This was the best representative sounding to describe the vertical profile of the prefrontal air: an (almost) saturated layer starting from a height of around 900 m (= 950 hPa), reaching up around 10 km (= 300 hPa). Attention must be paid to the fact that the temperature was in the entire sounding below zero, so 100% chance of the occurrence of snow. Prefrontal, the winds below 700 hPa were still coming from the SW.  (Source sounding: WetterOnline).

 

Forecasted sounding of Maastricht at 0700 CET. The saturated layer now starting from almost the ground up around 7 km (= 400 hPa). Entire sounding still well below zero, so 100% chance of the occurrence of snow. Gradually the winds began to veer, only below 850 hPa still westerlies.  (Source sounding: WetterOnline).

 

Forecasted sounding of Maastricht at 1300 CET. A saturated layer between 970-900 hPa and 700-500 hPa could only be responsible for light precipitation, the entire sounding still well below zero, so 100% chance of the occurrence of snow. The wind veered over the entire layer.  (Source sounding: WetterOnline).

 

Forecasted thickness map (in dam) between 1000-500 hPa of 05/01/2009 at 0100 CET. This calculation (or measurement) gives an idea on the kind of precipitation (solid or not). Usually in areas below 300 m, values below 528 dam produces (wet) wintry precipitation. (Source map: NOAA web server).

 

Forecasted thickness map (in dam) between 1000-500 hPa of 05/01/2009 at 0700 CET. Colder air is migrating southwards. Usually in areas below 300 m, values below 522 dam produces dry wintry precipitation. (Source map: NOAA web server).

 

Forecasted thickness map (in dam) between 1000-500 hPa of 05/01/2009 at 1300 CET. If precipitation is expected, only under form of dry solid form. (Source map: NOAA web server).

 

Forecasted thickness map (in dam) between 1000-850 hPa of 05/01/2009 at 0100 CET. This calculation (or measurement) gives one of the best ideas on the kind of precipitation, as this is done below 1500 m so the maritime component in the boundary layer is well weighted. Using the snow predictor of Boyden, which takes account of pressure and height, this tool gives an idea about the expectations of solid precipitation. In this case, with a pressure of 1010 hPa at height of 50 m, values of 128,5 dam or less give a probability of snow of 90 % or higher. On the other hand values of 129,0 or and higher give a probability of snow of less than 80 %. Clearly visible: over the western parts of Holland slightly warmer air is present, and moved further southwards. It was responsible for the fact that over extreme western parts of Belgium the light wintry precipitation mostly fell as a wet feature. (Source map: NOAA web server).

 

Forecasted thickness map (in dam) between 1000-850 hPa of 05/01/2009 at 0700 CET. Warmer air touching western parts of Belgium. (Source map: NOAA web server).

 

Forecasted thickness map (in dam) between 1000-850 hPa of 05/01/2009 at 1300 CET. Entire Belgium now in the freezing cold air with a chance dry solid precipitation, however by then, it remained dry over the extreme west of Belgium. (Source map: NOAA web server).

 

Below the observation sequence at Brussels Airport in UTC between 04/2150-05/1720, most recent one on top.

EBBR 051720Z 06010KT 9999 SCT016 SCT028 M03/M06 Q1022 R57/290174 R02/290176 NOSIG
EBBR 051650Z 05010KT 9999 -SN SCT016 BKN028 M03/M06 Q1022 R57/290174 R02/290176 NOSIG
EBBR 051620Z 06012KT 9999 BKN016 M02/M05 Q1021 R57/290174 R02/290176 NOSIG
EBBR 051550Z 05012KT 9999 -SN BKN015 M02/M05 Q1021 R57/290174 R02/290176 NOSIG
EBBR 051520Z 05012KT 9999 -SN SCT014 BKN020 M02/M05 Q1020 R57/290174 R02/290176 NOSIG
EBBR 051450Z 05012KT 9999 -SN SCT014 BKN023 M02/M05 Q1020 R57/290174 R02/290176 NOSIG
EBBR 051420Z 06013KT 9999 -SN SCT012 BKN018 M02/M05 Q1020 R25/490595 R02/490595 TEMPO 4000 -SN BKN008
EBBR 051350Z 06012KT 8000 -SN SCT008 BKN014 M02/M04 Q1019 R25/490595 R02/490595 TEMPO 4000 -SN BKN008
EBBR 051320Z 06012KT 9999 -SN FEW008 BKN014 M01/M04 Q1019 R25/490595 R02/490595 TEMPO 4000 -SN BKN008
EBBR 051250Z 06013KT 9000 FEW008 BKN013 M01/M04 Q1019 R25/490595 R02/490595 TEMPO 4000 -SN BKN008
EBBR 051220Z 05012KT 3000 -SG FEW005 BKN008 M01/M03 Q1018 R25/493025 R02/491576 R75/493025 NOSIG
EBBR 051150Z 06010KT 2500 R25L/P1500N R25R/1400N R02/P1500N -SG SCT005 BKN007 M00/M02 Q1018 R25/493025 R02/491576 R75/493025 NOSIG
EBBR 051120Z 06009KT 3000 -SG SCT005 BKN008 M00/M02 Q1018 R25/493025 R02/491576 R75/493025 NOSIG
EBBR 051050Z 06008KT 3000 R25L/P1500N R25R/P1500N R02/1400N -SG SCT005 BKN008 M01/M02 Q1018 R25/492521 R02/492525 R75/492520 NOSIG
EBBR 051020Z 06008KT 3000 -SN SCT005 BKN008 M01/M03 Q1017 R25/492521 R02/492525 R75/492520 BECMG 6000 NSW SCT008
EBBR 050950Z 06007KT 2500 -SN SCT003 BKN006 M01/M02 Q1017 R25/492521 R02/492525 R75/492520 BECMG 4000 NSW SCT006
EBBR 050920Z 05003KT 1200 R25L/P1500N R25R/1300N R02/P1500N -SN SCT002 BKN003 M01/M02 Q1016 R25/492521 R02/492525 R75/492520 NOSIG
EBBR 050850Z 06002KT 1000 R25L/P1500N R25R/1200N R02/1400N -SN SCT002 BKN004 M01/M02 Q1016 R25/492521 R02/492525 R75/492520 NOSIG
EBBR 050820Z 00000KT 0400 R25L/1400N R25R/1100D R02/P1500N +SN SCT002 BKN004 M01/M01 Q1015 R25/492521 R02/492525 R75/492520 NOSIG
EBBR 050750Z 00000KT 0800 R25L///// R25R///// R02///// -SN SCT004 BKN007 M00/M01 Q1015 R25/492521 R02/492525 R75/492520 TEMPO 0700 SN BKN004
EBBR 050720Z /////KT 0700 R25L///// R25R///// R02///// SN SCT004 BKN007 M00/M01 Q1014 R25/492521 R75/492520 TEMPO 0700 SN BKN004
EBBR 050650Z 21006KT 1000 R25L///// R25R///// R02///// SN FEW002 BKN007 M00/M01 Q1014 R25/492521 R75/492520 TEMPO 0800 SN BKN002
EBBR 050620Z 21008KT 1200 R25L///// R25R///// R02///// SN FEW002 BKN006 00/M01 Q1014 25652052 02652071 75652067 TEMPO 0800 SN BKN002
EBBR 050550Z /////KT 1200 R25L/P1500N R25R/1200N R02/P1500N SN FEW002 BKN006 M01/M02 Q1014 25652052 02652071 75652067 TEMPO 0800 SN BKN002
EBBR 050520Z 22008KT 1500 SN FEW003 BKN006 M01/M02 Q1014 25652052 02652071 75652067 TEMPO 0800 SN BKN002
EBBR 050450Z 23008KT 2000 -SN FEW003 BKN006 M01/M02 Q1014 25652052 02652071 75652067 TEMPO 0800 SN BKN002
EBBR 050420Z 22008KT 2000 -SN FEW003 BKN006 M01/M02 Q1014 25490434 02490431 75650270 TEMPO 0800 SN BKN002
EBBR 050350Z 23008KT 1500 -SN FEW003 BKN005 M01/M02 Q1014 25490434 02490431 75650270 TEMPO 0800 SN BKN002
EBBR 050320Z 24009KT 1700 -SN FEW005 BKN008 M01/M02 Q1014 25490354 75490363 TEMPO 0800 SN BKN002
EBBR 050250Z 24009KT 1700 -SN FEW003 BKN005 M01/M02 Q1015 25490354 75490363 TEMPO 0800 SN BKN002
EBBR 050220Z 24008KT 1700 R25L/P1500N R25R/0750VP1500U R02/P1500N -SN FEW006 BKN008 M01/M02 Q1015 25490354 75490363 NOSIG
EBBR 050150Z 24009KT 2300 -SN FEW006 BKN009 M01/M02 Q1015 25490354 75490363 NOSIG
EBBR 050120Z 24009KT 2500 -SN FEW006 BKN009 M01/M02 Q1015 25490354 75490363 NOSIG
EBBR 050050Z 23009KT 2700 -SN FEW011 BKN014 M01/M03 Q1015 BECMG 2000 -SN BKN012
EBBR 050020Z 23009KT 3000 -SN FEW011 BKN019 M01/M02 Q1016 BECMG 2000 -SN BKN012
EBBR 042350Z 23009KT 3200 -SN BKN019 M01/M03 Q1016 BECMG 2000 -SN BKN012
EBBR 042320Z 23010KT 3800 -SN BKN019 M01/M03 Q1016 BECMG 3000 -SN BKN012
EBBR 042250Z 23010KT 9999 BKN025 M00/M04 Q1017 BECMG 4000 -SN BKN012
EBBR 042220Z 24010KT 9999 FEW025 BKN030 M00/M04 Q1017 NOSIG
EBBR 042150Z 24011KT 9999 FEW024 BKN033 00/M04 Q1017 NOSIG

 

Snow depth in cm of 06/01 at 1000 CET gives a good idea about the coverage on regional scale. Over western parts 1 cm or less was measured, at Mont Rigi even 12 cm the day before (but here already 'collapsed'). 

 

05/01/2009 1056 NE. Village of Steenokkerzeel under a snow cover of 7 cm, still overcast with some light flurries. 

 

05/01/2009 1152 SE. Other side, the village of Humelgem, of course also under the same snow cover of 7 cm. 

 

05/01/2009 1102. An aircraft taxiing trough the snow, must be ages ago. 

 

05/01/09 1341. Same conditions at Kampenhout, the secondary roads still under that magnificent wintry carpet. 

 

05/01/09 1342. Not too much wind, so the trees & boughs also under this white blanket. 

 

05/01/09 1347. Classic view on 'Den Dreef". 

 

05/01/09 1355. Proof of the 7 cm 'white gold'. 

 

Analysis of the mean sea level pressure with fronts and 'plots' of 06/01/2009 at 0100 CET. High pressure cell 'Angelika' moved into the direction of Belgium. The skies became clear giving superb & bitterly cold wintry conditions on the second day. (Source chart: DWD)

 

Temperature of 06/01/2009 at 0800 CET. So just before sunset, this kind of deep frost didn't occur since January 1997. (Source chart: Wetterzentrale)

 

06/01/2009 0845 SE. Again at Steenokkerzeel: under bitterly cold conditions, catching the first rays of a rising sun. 

 

06/01/2009 0846 SE. Wider view. 

 

06/01/2009 0904 SE. Interesting to see I was not alone having cold. 

 

06/01/2009 0918. The contrast couldn't be bigger with this smoking C130 against the white carpet as background. 

 

06/01/2009 1100 NW. Mighty shadow of the tower. 

 

06/01/2009 1101 NNE. The 'sound wall' with behind the village Steenokkerzeel. 

 

06/01/2009 1523 SW. Cleaning of the runways/taxiways is done with this machine which literally blows away the snow with warm air. 

 

06/01/2009 1648 SW. After a beautiful day the sun was setting at the old control tower. 

 

06/01/2009 1650. Meanwhile the cleaning process of the runways & taxiways continued. 

 

06/01/2009 1705 NE. The pink horizontal band in the sky referred as 'Belt of Venus', with below a darker band which is nothing else than the (rising) shadow of the Earth). 

 

The crystal clear day gave the opportunity to have a view on Earth from space: clearly visible is a relative large area with snow on the ground. (Source: NOAA & University of Bern)

 

The Terra satellite gave a closer inspection on the situation over Belgium. (Source: Image courtesy of MODIS Rapid Response Project at NASA/GSFC)

 

Observed mean sea level surface chart of 2300 CET with the so called 'plots': one of the coldest nights in years was on its way. (Source chart: Meteocentre)

 

Observed minimum temperatures at 0700 CET of the night between 06-07/01: coldest spot was Ernage with -21,9°C. In my garden -17,6°C was measured. Soon after the sky was invaded with clouds and locally some slight wintry precipitation did fall. 

 

The couple days afterwards widespread freezing fog did occur, on January 9 it finally lifted resulting in a beautiful rimed landscape. The Terra satellite shows over western pars of  Belgium white spots, induced by so called 'industrial snow'. (Source: Image courtesy of MODIS Rapid Response Project at NASA/GSFC)

 

09/01/09 1118. At Kampenhout: every tree & bough covered by thick rime. 

 

09/01/09 1126. Same comment. 

 

09/01/09 1132. Play of light & shadow. 

 

09/01/09 1134. Snow and rime. 

 

09/01/09 1134. Same comment. 

 

09/01/09 1156. "Het Kanaal" between Mechelen and Leuven, not frozen yet. 

 

09/01/09 2340. Under an almost full Moon, a long exposure shot of  "Den Dreef". The temperature was -13°C. 

 

11/01/09 1122. At Steenokkerzeel. An alternative and cheap way of cleaning a runway: a departing aircraft. 

 

11/01/09 1249. At Kampenhout: after a couple of days, "Het Kanaal" showed more signs of being almost frozen. Even an ice breaker had gone trough, however this was the last day of very cold temperatures. 

 

12/01/09 0835 SE. Again at Steenokkerzeel: the next day, after a magnificent sunrise, it was all over. 

 

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