18

daily  temperatures  fell  to  about  -5°C  on  21  and  22  January,  with  minimum  temperatures
below  -7°C.  Water  temperatures  in  Trzebiez  and  Swinoujscie  fell  to  0°C,  and  in  Mi^dzyzdroje
to  -0.1  °C.  On  23  January,  southerly  air  flow  set  in  again,  with  air  temperatures  rising  slightly
until  26  January,  when  a  portion  of  warm  tropical  air  from  south-west  was  transported  as  far
north-east  as  the  Baltic  Sea  Basin.  Mean  daily  temperatures  around  Lagoon  rose  from  about
0°C  to  over  5°C.  The  last  remnants  of  sparse  snow  cover  disappeared.  Water  temperature  rose
from  0.2°C  on  25  January  to  1.5°C  on  29  January.  On  the  last  four  days  of  the  month,  the  air
cooled  again  to  slightly  negative  temperatures.
February
The  stationary  depression  that  had  developed  in  January  stayed  over  Western  and  Central
Europe;  secondary  lows  within  this  depression  were  not  very  active,  and  an  exchange  of  air
masses  was  usually  limited  to  the  polar  air  masses  with  small  thermal  contrasts.  Nevertheless,
occasional  intrusions  of  Arctic  air,  usually  transformed  over  the  ocean,  occurred  several
times.  In  the  first  days  of  the  month,  a  small  portion  of  Arctic  air  from  Scandinavia  arrived
over  the  southern  Baltic  Sea,  causing  cooler  temperatures  on  the  coasts.  Mean  daily
temperatures  around  Szczecin  Lagoon  fell  to  about  -3°C,  and  minimum  temperatures  to  -6°C.
The  water  temperature  in  Trzebiez  fell  to  +0.1  °C.  Between  4  and  9  February,  a  sequence  of
atmospheric  fronts  crossed  the  Baltic  Sea  basin,  followed  by  maritime  polar  air.  Temperatures
at  Szczecin  Lagoon  rose  to  positive.  The  mean  daily  values  on  6  to  8  February  were  4°C,  and
maxima  at  about  8°C.  However,  already  on  the  following  day,  behind  a  passing  depression,  a
new  portion  of  Arctic  air  arrived  in  the  area  of  Szczecin  Lagoon  and  caused  temperatures  to
fall  to  -2.4°C,  and  the  minimum  temperature  in  Trzebiez  to  -6.3°C.  On  10  February,  an
anticyclone  started  to  develop  over  Scandinavia  which  shifted  south-east  in  the  following
days  and  then  spread  eastward.  From  10  February,  the  anticyclone  led  to  the  development  of
an  easterly,  and  later  south-easterly,  air  flow  along  the  southern  coasts  of  the  Baltic  Sea.  Daily
temperatures  were  close  to  0°C,  and  only  on  19  February,  when  the  anticyclone  retreated  east,
did  a  south-westerly  air  flow  bring  warmer  air  into  the  area  (mean  daily  temperatures  from  2
to  9°C  on  cloudless  days),  causing  water  temperatures  to  rise  above  4°C  on  23  -  25  February.
Only  the  last  three  days  of  the  month,  from  26  February,  were  cooler  due  to  a  cold  front
passing  along  the  southern  coasts  of  the  Baltic  Sea,  followed  by  Arctic  air  masses.  Mean
daily  temperatures  dropped  to  about  -2°C,  and  the  minima  to  about  -5°C.
March
Another  intrusion  of  Arctic  air  occurred  on  1  March,  but  negative  air  temperatures  were
recorded  only  at  night,  in  the  vicinity  of  Szczecin  Lagoon.
Between  2  and  6  March,  a  rather  vigorous  westerly  air  flow  forced  its  way  eastward  over  the
northern  parts  of  Europe.  Along  the  southern  coasts  of  the  Baltic  Sea,  mild  maritime  polar  air
flowed  in.  Mean  daily  temperatures  oscillated  around  6°C.  Water  temperatures  rose  to  4°C.  On
6  March,  very  warm  maritime  polar  air  invaded  Europe,  spreading  north-east  as  far  as  Finland.
The  mean  daily  temperatures  over  Szczecin  Lagoon  rose  from  5°C  on  6  March  to  about  10°C
on  10  and  11  March.  This  warm  weather  lasted  until  19  March.  Water  temperatures  rose  to
about  8°C  on  those  days.  On  20  March,  a  high  pressure  zone  formed  over  Scandinavia  and
spread  eastward  on  the  following  days.  Air  flow  over  the  Southern  Baltic  Sea  gradually
changed  to  easterly.  The  previously  southerly  winds  backed  to  easterly  and  north-easterly
directions,  and  mean  daily  temperatures  oscillated  around  5°C.  On  24  March,  the  high  pressure
zone  moved  southward  from  Scandinavia,  followed  by  the  intrusion  of  Arctic  air  masses  which
gradually  penetrated  south  toward  the  British  Isles,  the  North  Sea  and  the  Baltic  Sea,  where  a
high  formed  on  29  and  30  March  creating  favourable  conditions  for  night  cooling.  On  29
March,  in  the  area  of  Szczecin  Lagoon,  mean  daily  air  temperatures  were  already  negative  and,